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 A337784 #15 Oct 05 2020 05:11:00
%S A337784 23256,530712,809100,11692980,17812620,20245500,22834062,23527350,
%T A337784 29154600,83768256,182236500,189847062,506227500,600127506,992218500,
%U A337784 1363566402,1640209500,2175895962,2422657620,2477899062,2520190602,3041687952,3764129256,4760103042
%N A337784 Smaller of two consecutive oblong numbers which are anagrams of each other.
%C A337784 All terms are multiples of 9.
%C A337784 The indices of these oblong numbers are 152, 728, 899, 3419, 4220, 4499, 4778, 4850, 5399, 9152, 13499, 13778, 22499, 24497, 31499, 36926, 40499, 46646, 49220, 49778, 50201, 55151, 61352, 68993.
%e A337784 530712 is in the sequence because it is an oblong number, 530712 = 728 * 729, and the next oblong number, 532170 = 729 * 730, is an anagram of 530712.
%t A337784 s = {}; o1 = 1; d1 = Sort @ IntegerDigits[o1]; Do[o2 = n*(n + 1); d2 = Sort @ IntegerDigits[o2]; If[d2 == d1, AppendTo[s, o1]]; o1 = o2; d1 = d2, {n, 2, 70000}]; s (* _Amiram Eldar_, Sep 21 2020 *)
%o A337784 (PARI) ok(k) = {my(b, m=0); if(issquare(4*k + 1), b=truncate(sqrt(4*k + 1) - 1)/2; if(vecsort(digits(k)) == vecsort(digits((b + 1)*(b + 2))), m = 1)); m}
%Y A337784 Subsequence of A008591.
%Y A337784 Cf. A002378, A069567, A227692, A228133, A228135.
%K A337784 nonn,base
%O A337784 1,1
%A A337784 _Antonio Roldán_, Sep 21 2020