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 A272524 #12 Jul 17 2019 15:57:57 %S A272524 1,36,136,276,1176,2016,2556,2628,3240,4560,11628,12720,12880,18336, %T A272524 18528,25200,32640,32896,51360,64620,73920,86320,89676,100128,114960, %U A272524 115440,126756,131328,148240,166176,248160,253116,265356,270480,294528,295296,320400,345696,373680,380628,400960,401856,438516 %N A272524 Refactorable triangular numbers. %C A272524 Intersection of A000217 and A033950. %H A272524 Amiram Eldar, <a href="/A272524/b272524.txt">Table of n, a(n) for n = 1..10000</a> %e A272524 36 is a term as the number of divisors of 36 (see A000005) is 9 which divides 36. %t A272524 Select[PolygonalNumber@Range@1000, Divisible[#, DivisorSigma[0,#]]&] %o A272524 (PARI) for (n=1, 1000, t=n*(n+1)/2; t%numdiv(t)==0 && print1(t ", " )) %Y A272524 Cf. A000217 (triangular numbers), A033950 (refactorable numbers), A063440 (number of divisors of triangular numbers), A000005 (number of divisors), A036907 (refactorable squares). %K A272524 nonn %O A272524 1,2 %A A272524 _Waldemar Puszkarz_, May 01 2016