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 A278251 #8 Nov 22 2016 21:49:52 %S A278251 1,1,2,2,2,6,2,2,6,2,6,6,6,2,6,2,2,30,2,8,6,2,2,12,6,2,30,6,2,6,6,12, %T A278251 6,6,2,6,6,6,30,2,6,6,2,6,6,6,6,30,6,6,30,2,6,6,6,2,30,6,2,30,2,6,30, %U A278251 2,6,30,6,2,60,12,2,6,2,6,6,30,2,6,2,2,60,2,30,6,6,6,6,6,30,30,2,2,6,6,6,30,6,6,6,6,2,210,2,30,6,6,2,30,30,6,30,2,2 %N A278251 Least number with the prime signature of the n-th central polygonal number. %C A278251 Almost all terms seem to be primorials, 4871 of the first 5212, in other words, most terms of A002061 (in the same range) are squarefree. %H A278251 Antti Karttunen, <a href="/A278251/b278251.txt">Table of n, a(n) for n = 0..5211</a> %F A278251 a(n) = A046523(A002061(n)). %o A278251 (Scheme) (define (A278251 n) (A046523 (A002061 n))) %Y A278251 Cf. A002061, A046523. %Y A278251 Cf. also A278246, A278247, A278253. %K A278251 nonn %O A278251 0,3 %A A278251 _Antti Karttunen_, Nov 21 2016