## Tag: number-theory

202 Is this number a prime? 2015-09-11T14:06:29.040

73 Calculate Phi (not Pi) 2015-11-12T23:56:22.273

70 Well that's odd... no wait, that's even! 2015-12-02T10:22:24.003

67 Is this even or odd? 2017-03-21T10:30:34.823

67 Yo boy, must it sum 2017-10-23T15:39:46.720

66 Calculate the number of primes up to n 2016-02-26T19:08:02.277

60 Find the Smoothest Number 2014-08-18T23:30:24.447

51 Coprimes up to N 2016-12-26T18:00:02.387

51 Find the smallest number that doesn't divide N 2017-01-03T08:50:00.077

51 Bringing a pair of integers to equality 2018-05-03T14:15:28.510

46 Count sums of two squares 2015-11-26T00:38:01.640

46 Divisor skyline 2017-05-07T16:31:21.547

44 Theoretically output Graham's number 2016-06-27T07:30:45.190

42 A naturally occurring prime generator 2015-08-25T06:31:23.077

40 Greatest Common Divisor 2016-04-07T05:29:54.567

40 Sharing (characters) is Caring! 2017-01-09T19:14:10.043

40 Am I divisible by double the sum of my digits? 2017-07-03T13:00:47.433

39 Pseudofactorial 2016-06-09T20:19:47.310

38 Is this number evil? 2018-08-01T15:08:21.957

37 Is it a Proth number? 2016-08-10T22:07:56.617

37 Abandon all squares, ye who divide me 2017-05-11T15:56:28.810

36 Catalan Numbers 2015-12-09T17:39:41.920

36 Compute the Carmichael function 2016-09-18T18:07:49.620

36 Incrementing Gray Codes 2016-10-02T21:05:35.577

36 Replace twos with threes 2017-05-04T21:45:59.043

35 The Arithmetic Derivative 2016-04-03T11:23:22.977

35 Is it a Mersenne Prime? 2016-12-25T14:18:05.567

35 Sum the powers that be 2017-02-10T09:00:40.570

34 Can you reach this number by doubling and rearranging? 2015-08-19T08:38:05.383

34 Sum of Modulo Sums 2016-12-09T14:36:54.233

33 Is this number Loeschian? 2016-08-04T15:34:41.337

33 Finding The nth Prime such that the prime - 1 is divisible by n 2016-11-17T03:07:25.513

33 Can square tree rings be generated from primes? 2018-01-30T21:28:35.197

33 (RGS 1/5) Binary multiples 2020-02-24T08:02:19.677

32 Standardise a Phinary Number 2014-09-16T13:00:11.690

32 Array Escape - get out of there 2016-07-25T11:08:57.993

32 Score Tarzan's Olympic Vine-Swinging Routine 2016-08-20T14:38:09.433

32 1, 2, 3, 14... or is it 15? 2018-03-30T22:11:53.260

31 Least Common Multiple 2016-09-30T18:47:53.850

31 Are you lost yet? 2016-12-24T04:18:03.893

31 Find the dot product of Rationals 2018-02-22T22:30:39.610

30 That's a prime... almost 2016-02-22T17:36:42.077

29 Generate Keyboard Friendly Numbers 2015-05-12T04:58:46.287

29 Addition on Elliptic Curves 2016-03-18T20:59:23.433

29 Pascal's Column Sums 2017-03-16T14:27:12.067

29 Primitive Pythagorean Triples 2017-07-25T13:20:56.090

29 Am I not good enough for you? 2019-03-12T02:41:31.763

29 Longest Prime Sums 2019-12-11T23:04:49.113

28 Visualize the greatest common divisor 2016-01-01T19:15:52.260

28 One-zero dividend 2016-02-28T15:11:27.560

28 Is this a Smith number? 2016-09-02T14:27:24.987

28 List all multiplicative partitions of n 2016-12-26T22:38:07.357

28 Smallest unseen, but no sharing digits! 2017-08-10T15:03:15.687

28 Fundamental Solution of the Pell Equation 2019-04-16T13:37:52.573

28 Fermat's Last Theorem, mod n 2019-11-04T16:33:10.583

27 Calculate n % 12 2014-06-20T00:05:32.077

27 Calculate Euler's totient function 2016-06-22T06:50:27.523

27 Numbers of purity 2016-08-12T20:23:51.227

27 Which Day of Christmas is it? 2017-01-27T17:14:49.457

27 Is it a Chen prime? 2017-07-10T11:54:59.060

27 Find prime gaps 2017-08-03T18:31:13.517

27 Is this a three-digit number ending in one? 2017-12-16T09:21:24.847

26 Am I perfect (number)? 2015-09-15T21:39:15.693

26 Count the divisors of a number 2015-11-27T06:19:14.787

26 AGM Series Hole 1: Calculate the Arithmeticâ€“Geometric Mean 2015-12-08T22:57:51.977

26 Residue Number System 2016-02-13T06:16:27.700

26 Swap bits with their neighbours 2016-06-03T22:42:34.207

26 Is it a weak prime? 2017-07-08T16:33:32.613

26 Diluted Integer Sums 2018-01-29T15:04:30.570

26 Who's next to me in the queue? 2019-12-08T20:12:58.900

25 What's a half on the clock? 2015-12-28T23:00:56.100

25 Implement the divisibility-by-7 rule 2016-02-14T19:58:53.913

25 Generate lazy values 2016-02-23T02:49:54.770

25 Approximate Brun's Constant 2017-01-22T00:31:45.340

25 Deranged !Combinatorics: Compute the Subfactorial 2017-03-26T17:00:19.690

25 GET your dubs together 2017-03-28T08:51:40.363

25 Palindromic Residue 2017-03-31T14:57:16.960

24 Print all 3 by 3 sturdy squares 2015-10-21T22:47:52.950

24 Decimal concatenation of squares 2015-11-13T20:59:51.217

24 Write numbers as a difference of Nth powers 2018-01-14T15:06:30.543

24 Pascal's Triangle (Sort of) 2018-02-07T13:51:21.443

24 Bertrand's Primes 2018-02-13T15:27:27.247

24 Find the 10-adic cube root of 3 2018-06-07T10:24:54.223

24 Fermat's polygonal number theorem 2019-10-07T17:13:49.750

24 Next Shared Totient 2019-12-04T20:07:38.677

23 Find the prime factors 2011-04-06T20:01:14.137

23 Co-primality and the number pi 2015-12-26T16:16:32.960

23 The MÃ¶bius Function 2016-01-24T13:54:37.050

23 Highly composite numbers 2016-02-29T22:26:04.020

23 Partial factorisations of a positive integer 2016-07-29T06:05:22.490

23 Divinacci Sequence 2017-06-23T13:51:34.740

23 Factorize a Gaussian integer 2017-07-12T21:37:22.707

23 Modular multiplicative inverse 2017-08-24T15:41:12.173

22 Last non-zero digit of n! 2011-02-08T09:03:33.850

22 Generate Lucky Numbers 2015-02-17T03:57:38.097

22 Factoring a 64-bit integer 2015-04-23T23:22:55.783

22 Last Nonzero Digits of a Factorial in Base 2015-04-30T12:54:34.810