This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
Brian Kell has authored 4 sequences.
The following is a 4 X 4 Takuzu grid: [ 0 1 1 0 ] [ 1 0 0 1 ] [ 0 0 1 1 ] [ 1 1 0 0 ]
For n=2 the a(2)=12 partitions of a 2x2 square are: 1 partition into a single 2x2 region; 4 partitions into a 3-square 'L' shape and an isolated corner; 2 partitions into 2 1x2 bricks; 4 partitions into a 1x2 brick and 2 isolated squares; and 1 partition into 4 isolated squares.
k = 5 is here because 4*5! - 1 = 479 is prime.
for n from 0 to 1000 do if isprime(4*n! - 1) then print(n) end if end do;
For[n = 0, True, n++, If[PrimeQ[4 n! - 1], Print[n]]] (* Jean-François Alcover, Sep 23 2015 *)
is_A099350(n)=ispseudoprime(n!*4-1) \\ M. F. Hasler, Sep 20 2015
k = 5 is here because 5*5! - 1 = 599 is prime.
for n from 0 to 1000 do if isprime(5*n! - 1) then print(n) end if end do;
Select[Range[550],PrimeQ[5#!-1]&] (* Harvey P. Dale, Nov 27 2013 *)
is(n)=ispseudoprime(5*n!-1) \\ Charles R Greathouse IV, Jun 13 2017
from sympy import isprime from math import factorial print([k for k in range(300) if isprime(5*factorial(k) - 1)]) # Michael S. Branicky, Mar 05 2021
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