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Number of compositions of 2n into parts with distinct multiplicities and with exactly n parts.
2

%I #11 Jan 06 2019 13:47:56

%S 1,1,1,4,5,6,142,428,1269,3874,20336,114522,429002,1743184,6456192,

%T 23749014,93997909,368890906,1122546076,4496925530,17437145160,

%U 76147395524,310155556998,1417665712388,5528899930962,21923449788406,82833896451112,347234278501138

%N Number of compositions of 2n into parts with distinct multiplicities and with exactly n parts.

%H Vaclav Kotesovec, <a href="/A321772/b321772.txt">Table of n, a(n) for n = 0..131</a> (terms 0..100 from Alois P. Heinz)

%F a(n) = A242887(2n,n).

%e a(0) = 1: the empty composition.

%e a(1) = 1: 2.

%e a(2) = 1: 22.

%e a(3) = 4: 222, 114, 141, 411.

%Y Cf. A242887.

%K nonn

%O 0,4

%A _Alois P. Heinz_, Nov 18 2018