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.

A331980 Number of compositions (ordered partitions) of n into distinct odd parts > 1.

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%I A331980 #8 Apr 15 2022 12:09:16
%S A331980 1,0,0,1,0,1,0,1,2,1,2,1,4,1,4,7,6,7,6,13,8,19,8,25,34,31,34,43,60,49,
%T A331980 84,61,134,73,158,205,232,217,280,355,378,487,450,745,572,1003,668,
%U A331980 1381,1558,1759,1678,2383,2592,3001,3480,3865,5162,4729,6794,5953,9964
%N A331980 Number of compositions (ordered partitions) of n into distinct odd parts > 1.
%H A331980 <a href="/index/Com#comp">Index entries for sequences related to compositions</a>
%F A331980 G.f.: Sum_{k>=0} k! * x^(k*(k + 2)) / Product_{j=1..k} (1 - x^(2*j)).
%e A331980 a(12) = 4 because we have [9, 3], [7, 5], [5, 7] and [3, 9].
%t A331980 nmax = 60; CoefficientList[Series[Sum[k! x^(k (k + 2))/Product[(1 - x^(2 j)), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]
%Y A331980 Cf. A000931, A027349, A032020, A032021, A032022, A087897.
%K A331980 nonn
%O A331980 0,9
%A A331980 _Ilya Gutkovskiy_, Feb 03 2020