A158142 - OEIS

%I #4 Mar 31 2012 12:35:25

%S 1,4,9,25,46,103,163,307,478,791,1143,1818,2495,3663,4994,7002,9154,

%T 12532,15986,21200,26726,34398,42532,54145,65791,81872,98871,121163,

%U 144174,175083,206075,246947,289116,342271,397027,467462,537495,626427

%N Number of nondecreasing integer sequences of length 8 with sum zero and sum of absolute values 2n.

%C a(n) = A000041(n)^2 for n<=4

%C a(n) = A000041(n)^2 - cumulative A000712(2*n-1-length), 0 <= 2*n-1-length <= floor(n/2) [empirical].

%H R. H. Hardin, <a href="/A158142/b158142.txt">Table of n, a(n) for n=1..689</a>

%K nonn

%O 1,2

%A _R. H. Hardin_ Mar 13 2009