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 A220692 #12 Mar 31 2025 23:10:15
%S A220692 0,1,0,3,0,0,6,1,1,0,10,2,1,0,0,15,4,2,1,0,0,21,6,4,1,1,0,0,28,9,5,2,
%T A220692 2,0,0,0,36,12,7,3,2,1,0,0,0,45,16,10,5,3,2,1,0,0,0,55,20,12,6,4,2,2,
%U A220692 0,0,0,0,66,25,15,8,6,3,3,1,0,0,0,0
%N A220692 Square array A220691 transposed.
%H A220692 <a href="/index/Su#subsetsums">Index entries for sequences related to subset sums modulo m</a>
%F A220692 a(n) = A220691bi(A004736(n),A002260(n)). (As a sequence. As an array this is the transpose of the square array given in A220691).
%t A220692 a[n_, 1] := n*(n-1)/2; a[n_, k_] := Module[{r}, r = Reduce[1 <= i < j <= n && Mod[i+j, k] == 0, {i, j}, Integers]; Which[Head[r] === Or, Length[r], Head[r] === And, 1, r === False, 0, True, Print[r, " not parsed"]]]; Table[a[n-k+1, k], {n, 1, 13} , {k, 1, n}] // Flatten (* _Jean-François Alcover_, Mar 04 2014 *)
%o A220692 (Scheme) (define (A220692 n) (A220691bi (A004736 n) (A002260 n)))
%Y A220692 Cf. A220691, A220693, A061857.
%K A220692 nonn,tabl
%O A220692 1,4
%A A220692 _Antti Karttunen_, Feb 18 2013