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 A306518 #6 Feb 16 2025 08:33:55
%S A306518 1,1,2,1,2,0,1,2,2,0,1,2,0,4,2,1,2,2,2,2,0,1,2,0,4,6,0,0,1,2,2,0,4,0,
%T A306518 4,0,1,2,0,6,2,4,0,0,0,1,2,2,0,6,2,8,4,2,2,1,2,0,4,2,4,4,8,0,6,0,1,2,
%U A306518 2,2,4,0,14,0,6,2,0,0,1,2,0,4,6,4,0,8,0,6,0,4,0,1,2,2,0,2,0,8,2,6,6,8,0,4,0
%N A306518 Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of Product_{d|k} theta_3(q^d).
%H A306518 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/JacobiThetaFunctions.html">Jacobi Theta Functions</a>
%F A306518 G.f. of column k: Product_{d|k} theta_3(q^d).
%e A306518 Square array begins:
%e A306518 1, 1, 1, 1, 1, 1, ...
%e A306518 2, 2, 2, 2, 2, 2, ...
%e A306518 0, 2, 0, 2, 0, 2, ...
%e A306518 0, 4, 2, 4, 0, 6, ...
%e A306518 2, 2, 6, 4, 2, 6, ...
%e A306518 0, 0, 0, 4, 2, 4, ...
%t A306518 Table[Function[k, SeriesCoefficient[Product[EllipticTheta[3, 0, q^d], {d, Divisors[k]}], {q, 0, n}]][i - n + 1], {i, 0, 13}, {n, 0, i}] // Flatten
%Y A306518 Columns k=1..48 give A000122, A033715, A033716, A033717, A033718, A033712, A033719, A033720, A033721, A033722, A033723, A033724, A033725, A033726, A033727, A033728, A033729, A033730, A033731, A033732, A033733, A033734, A033735, A033736, A033737, A033738, A033739, A033740, A033741, A033742, A033743, A033744, A033745, A033746, A033747, A033748, A033749, A033750, A033751, A033752, A033753, A033754, A033755, A033756, A033757, A033758, A033759, A033760.
%Y A306518 Cf. A320305 (diagonal).
%K A306518 nonn,tabl
%O A306518 0,3
%A A306518 _Ilya Gutkovskiy_, Feb 21 2019