cp's OEIS Frontend

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.

A286957 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1 + k*x^j).

This page as a plain text file.
%I A286957 #11 Sep 09 2017 07:05:34
%S A286957 1,1,0,1,1,0,1,2,1,0,1,3,2,2,0,1,4,3,6,2,0,1,5,4,12,6,3,0,1,6,5,20,12,
%T A286957 10,4,0,1,7,6,30,20,21,18,5,0,1,8,7,42,30,36,48,22,6,0,1,9,8,56,42,55,
%U A286957 100,57,30,8,0,1,10,9,72,56,78,180,116,84,42,10,0,1,11,10,90,72,105,294,205,180,120,66,12,0
%N A286957 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1 + k*x^j).
%C A286957 A(n,k) is the number of partitions of n into distinct parts of k sorts: the parts are unordered, but not the sorts.
%H A286957 Seiichi Manyama, <a href="/A286957/b286957.txt">Antidiagonals n = 0..139, flattened</a>
%H A286957 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A286957 G.f. of column k: Product_{j>=1} (1 + k*x^j).
%e A286957 Square array begins:
%e A286957 1,  1,   1,   1,   1,   1,  ...
%e A286957 0,  1,   2,   3,   4,   5,  ...
%e A286957 0,  1,   2,   3,   4,   5,  ...
%e A286957 0,  2,   6,  12,  20,  30,  ...
%e A286957 0,  2,   6,  12,  20,  30,  ...
%e A286957 0,  3,  10,  21,  36,  55,  ...
%t A286957 Table[Function[k, SeriesCoefficient[Product[(1 + k x^i), {i, 1, Infinity}], {x, 0, n}]][j - n], {j, 0, 12}, {n, 0, j}] // Flatten
%t A286957 Table[Function[k, SeriesCoefficient[QPochhammer[-k, x]/(1 + k), {x, 0, n}]][j - n], {j, 0, 12}, {n, 0, j}] // Flatten
%Y A286957 Columns k=0-5 give: A000007, A000009, A032302, A032308, A261568, A261569.
%Y A286957 Main diagonal gives A291698.
%Y A286957 Cf. A246935.
%K A286957 nonn,tabl
%O A286957 0,8
%A A286957 _Ilya Gutkovskiy_, May 17 2017