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.
%I A285811 #9 Apr 27 2017 10:38:59 %S A285811 2,23,107,149,317,1619,2459,3257,3929,5189,6029,6323,7247,15017,19427, %T A285811 21023,21569,26189,42737,45887,55127,56009,63317,66173,67139,70079, %U A285811 82469,101747,105359,110273,125687,136523,137909,149249,155087,159539,167099,171719 %N A285811 Primes equal to a centered heptagonal number plus 1. %C A285811 Primes in A209294. - _Omar E. Pol_, Apr 27 2017 %H A285811 Colin Barker, <a href="/A285811/b285811.txt">Table of n, a(n) for n = 1..1000</a> %o A285811 (PARI) cpg(m, n) = m*n*(n-1)/2+1 \\ n-th centered m-gonal number %o A285811 maxk=600; L=List(); for(k=1, maxk, if(isprime(p=cpg(7, k) + 1), listput(L, p))); Vec(L) %Y A285811 Cf. A000040, A069099, A285809, A285810, A285812. %K A285811 nonn %O A285811 1,1 %A A285811 _Colin Barker_, Apr 27 2017