Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #4 Mar 31 2012 12:35:26
%S 1,4,9,25,49,121,222,466,828,1537,2546,4506,7097,11656,17964,28080,
%T 41533,62829,90245,131868,185633,262931,361620,502438,677292,919091,
%U 1221175,1627409,2126641,2793158,3599216,4655834,5933603,7571871,9539554
%N Number of nondecreasing integer sequences of length 12 with sum zero and sum of absolute values 2n.
%C a(n) = A000041(n)^2 for n<=6
%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="/A158146/b158146.txt">Table of n, a(n) for n=1..474</a>
%K nonn
%O 1,2
%A _R. H. Hardin_ Mar 13 2009