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 A364691 #26 Oct 07 2023 07:01:03
%S A364691 0,5,13490,3299391550,22042432252064127,2387505511919644051,
%T A364691 680588297594638712735
%N A364691 Pentagonal numbers which are the sum of the first k primes, for some k >= 0.
%H A364691 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagonal_number">Pentagonal number</a>.
%H A364691 <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%e A364691 5 is a term because it's both a pentagonal number and the sum of the first two primes (2 + 3).
%t A364691 A364691list[kmax_]:=Module[{p=0},Join[{0},Table[If[IntegerQ[(Sqrt[24(p+=Prime[k])+1]+1)/6],p,Nothing],{k,kmax}]]];A364691list[25000] (* _Paolo Xausa_, Oct 06 2023 *)
%o A364691 (PARI) ispenta(n) = my(s); issquare(24*n+1,&s)&&s%6==5;
%o A364691 my(S=0); forprime (p=2, oo, S+=p; if (ispenta(S), print1(S,", "))) \\ _Hugo Pfoertner_, Aug 03 2023
%Y A364691 Intersection of A000326 with A007504.
%Y A364691 Cf. A066527, A061890, A364694, A364696, A366269.
%K A364691 nonn,hard,more
%O A364691 1,2
%A A364691 _Paolo Xausa_, Aug 03 2023
%E A364691 a(5)-a(7) from _Hugo Pfoertner_, Aug 04 2023