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.

A236429 Number of representations of 0 as a sum of numbers d*k with d in {-1,1} and k in {1,2,...,n}, where the sum of the numbers k is 2n.

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%I A236429 #11 Nov 06 2018 04:21:22
%S A236429 1,3,6,14,25,52,86,160,260,443,688,1146,1721,2716,4040,6176,8975,
%T A236429 13482,19218,28167,39799,57081,79503,112987,155368
%N A236429 Number of representations of 0 as a sum of numbers d*k with d in {-1,1} and k in {1,2,...,n}, where the sum of the numbers k is 2n.
%C A236429 a(n) = number of partitions of 2n that contain a partition of n.
%e A236429 a(3) counts these 6 representations of 0: 3-3, 3-2-1, 3-1-1-1, 2+1-2-1, 2+1-1-1-1, 1+1+1-1-1-1.
%t A236429 p[n_] := p[n] = IntegerPartitions[n]; Map[({p1 = p[#], p2 = p[2 #]} &[#];    Length[Cases[p2, Apply[Alternatives, Map[Flatten[{___, #, ___}] &, p1]]]]) &,  Range[12]]
%t A236429 Map[({p1 = p[# + 1], p2 = p[2 # + 1]} &[#]; Length[Cases[p2, Apply[Alternatives, Map[Flatten[{___, #, ___}] &, p1]]]]) &, Range[12]]
%t A236429 (* _Peter J. C. Moses_, Jan 04 2014 *)
%Y A236429 Cf. A236430, A235130.
%K A236429 nonn,more
%O A236429 1,2
%A A236429 _Clark Kimberling_, Jan 25 2014