A258471 - OEIS

%I #7 May 31 2015 17:25:13

%S 1,3,11,41,155,590,2258,8677,33454,129335,501180,1945997,7569223,

%T 29487091,115029830,449288570,1756808604,6876430799,26940317004,

%U 105635470645,414528962220,1627841401281,6396735649200,25152046015693,98955167336425,389526824102747

%N Number of partitions of 2n into two sorts of parts having exactly n parts of the second sort.

%H Alois P. Heinz, <a href="/A258471/b258471.txt">Table of n, a(n) for n = 0..300</a>

%F a(n) = A256193(2n,n).

%F a(n) ~ c * 4^n / sqrt(Pi*n), where c = 1 / A048651 = 1 / Product_{k>=1} (1-1/2^k) = 3.462746619455... . - _Vaclav Kotesovec_, May 31 2015

%Y Cf. A256193.

%K nonn

%O 0,2

%A _Alois P. Heinz_, May 31 2015