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 A382451 #8 Mar 31 2025 21:27:11
%S A382451 5406,12426,20026,23766,40641,55131,83266,115026,118266,136306,142206,
%T A382451 145806,176226,184281,205206,209526,245706,279726,284766,315951,
%U A382451 326706,371526,387106,407031,413106,419226,425391,498406,505126,553426,623751,638826,672106,685131
%N A382451 Centered pentagonal numbers which are the products of four distinct primes.
%e A382451 A005891(46) = 5406 = (5*46^2 + 5*46 + 2)/2 = 2*3*17*53.
%e A382451 A005891(70) = 12426 = (5*70^2 + 5*70 + 2)/2 = 2*3*19*109.
%e A382451 A005891(127) = 40641 = (5*127^2 + 5*127 + 2)/2 = 3*19*23*31.
%t A382451 Select[Table[5*n*(n+1)/2+1, {n, 0, 600}], FactorInteger[#][[;; , 2]] == {1, 1, 1, 1} &] (* _Amiram Eldar_, Mar 26 2025 *)
%Y A382451 Intersection of A005891 and A046386.
%Y A382451 Cf. A364610.
%K A382451 nonn
%O A382451 1,1
%A A382451 _Massimo Kofler_, Mar 26 2025