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 A278253 #17 Feb 03 2017 15:30:43
%S A278253 1,2,6,6,6,6,12,36,12,6,30,30,6,30,120,24,12,12,30,210,30,6,60,180,12,
%T A278253 24,120,30,30,30,48,240,30,30,420,60,6,30,420,60,30,30,30,420,60,6,
%U A278253 120,360,36,60,210,30,24,120,420,420,30,6,210,210,6,60,1440,480,210,30,30,210,210,30,180,180,6,60,420,210,210,30,120,2160,48,6,210,2310,30,30
%N A278253 Least number with the prime signature of the n-th triangular number.
%H A278253 Antti Karttunen, <a href="/A278253/b278253.txt">Table of n, a(n) for n = 1..10000</a>
%F A278253 a(n) = A046523(A000217(n)).
%t A278253 Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]]] &@ FactorInteger[ (n^2 - n)/2], {n, 2, 87}] (* _Michael De Vlieger_, Nov 21 2016 *)
%o A278253 (Scheme) (define (A278253 n) (A046523 (A000217 n)))
%o A278253 (PARI) a(n)=my(f=vecsort(factor(n*(n+1)/2)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]) \\ _Charles R Greathouse IV_, Feb 03 2017
%Y A278253 Cf. A000217, A046523, A278254, A278256.
%Y A278253 Diagonal 2 of triangle A278218.
%K A278253 nonn
%O A278253 1,2
%A A278253 _Antti Karttunen_, Nov 19 2016