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.
4 is in this sequence because 6 * 7^4 + 1 = 14407, which is prime.
Select[Range[0,200000], PrimeQ[6 * 7^# + 1] &]
[n: n in [0..4000] | IsPrime(12*3^n + 1)];
Select[Range[4000], PrimeQ[12 * 3^# + 1] &]
is(n)=ispseudoprime(12*3^n+1) \\ Charles R Greathouse IV, Jun 13 2017
[n: n in [0..4000] | IsPrime(14*3^n+1)];
Select[Range[4000], PrimeQ[14 3^# + 1] &]
is(n)=ispseudoprime(14*3^n+1) \\ Charles R Greathouse IV, Jun 13 2017
3 is a term because 6*3^3 + 1 = 163 is prime. 7 is not a term because 6*3^7 + 1 = 13123 = 11*1193 is composite.
/* Gives only the terms up to 1453: */ [n: n in [0..1500] | IsPrime(6*3^n + 1)];
Select[Range[5000], PrimeQ[6 3^# + 1] &]
is(n)=ispseudoprime(6*3^n+1) \\ Charles R Greathouse IV, Jun 13 2017
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