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 A276264 #12 Feb 16 2025 08:33:36
%S A276264 151,251,701,1951,3001,4751,10151,12401,16651,19501,28201,29401,33151,
%T A276264 38501,39901,45751,56951,63901,65701,81001,87151,95701,104651,114001,
%U A276264 136501,144451,147151,158201,178501,181501,193751,219451,232901,257401,275651,290701,318001,322001
%N A276264 Centered 25-gonal primes.
%C A276264 Primes of the form (25*k^2 + 25*k + 2)/2.
%C A276264 Numbers k such that (25*k^2 + 25*k + 2)/2 is prime: 3, 4, 7, 12, 15, 19, 28, 31, 36, 39, 47, 48, 51, 55, 56, 60, 67, 71, 72, 80, 83, 87, 91, ...
%H A276264 Robert Israel, <a href="/A276264/b276264.txt">Table of n, a(n) for n = 1..10000</a>
%H A276264 OEIS Wiki, <a href="http://oeis.org/wiki/Centered_polygonal_numbers#cite_note-1">Centered polygonal numbers</a>
%H A276264 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CenteredPolygonalNumber.html">Centered Polygonal Number</a>
%H A276264 <a href="/index/Ce#CENTRALCUBE">Index entries for sequences related to centered polygonal numbers</a>
%p A276264 select(isprime, [seq((25*k^2+25*k+2)/2, k=1..200)]); # _Robert Israel_, Sep 01 2016
%t A276264 Intersection[Table[(25 k^2 + 25 k + 2)/2, {k, 0, 1000}], Prime[Range[28000]]]
%o A276264 (PARI) lista(nn) = for(n=1, nn, if(isprime(p=(25*n^2 + 25*n + 2)/2), print1(p, ", "))); \\ _Altug Alkan_, Aug 26 2016
%Y A276264 Cf. A000040, A262221.
%Y A276264 Cf. centered k-gonal primes listed in A276261.
%K A276264 nonn
%O A276264 1,1
%A A276264 _Ilya Gutkovskiy_, Aug 26 2016