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 A285425 #29 Feb 16 2025 08:33:43
%S A285425 1,1,1,1,1,2,1,1,4,1,1,1,10,1,2,1,1,28,1,6,2,1,1,82,1,26,4,2,1,1,244,
%T A285425 1,126,10,8,1,1,1,730,1,626,28,50,1,3,1,1,2188,1,3126,82,344,1,13,2,1,
%U A285425 1,6562,1,15626,244,2402,1,91,6,2,1,1,19684,1,78126,730,16808,1,757,26,12,2
%N A285425 Square array A(n,k), n>=1, k>=0, read by antidiagonals, where column k is the expansion of Sum_{j>=1} (2*j - 1)^k*x^(2*j-1)/(1 - x^(2*j-1)).
%C A285425 A(n,k) is the sum of k-th powers of odd divisors of n.
%H A285425 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OddDivisorFunction.html">Odd Divisor Function</a>
%H A285425 <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>
%F A285425 G.f. of column k: Sum_{j>=1} (2*j - 1)^k*x^(2*j-1)/(1 - x^(2*j-1)).
%e A285425 Square array begins:
%e A285425 1, 1, 1, 1, 1, 1, ...
%e A285425 1, 1, 1, 1, 1, 1, ...
%e A285425 2, 4, 10, 28, 82, 244, ...
%e A285425 1, 1, 1, 1, 1, 1, ...
%e A285425 2, 6, 26, 126, 626, 3126, ...
%e A285425 2, 4, 10, 28, 82, 244, ...
%t A285425 Table[Function[k, SeriesCoefficient[Sum[(2 i - 1)^k x^(2 i - 1)/(1 - x^(2 i - 1)), {i, 1, n}], {x, 0, n}]][j - n], {j, 0, 12}, {n, 1, j}] // Flatten
%Y A285425 Columns k=0-5 give: A001227, A000593, A050999, A051000, A051001, A051002.
%Y A285425 Cf. A109974, A279394, A292919.
%K A285425 nonn,tabl
%O A285425 1,6
%A A285425 _Ilya Gutkovskiy_, May 14 2017
%E A285425 Offset changed by _Ilya Gutkovskiy_, Oct 25 2018