The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
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 1,4,9,25,49,121,224,476,862,1629,2750,4942,7947,13290,20892,33272,
%T 50229,77373,113409,168716,242193,349279,489700,692174,950812,1312535,
%U 1775675,2406215,3200557,4271720,5600464,7359874,9536595,12359775,15825600
%N Number of nondecreasing integer sequences of length 13 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="/A158147/b158147.txt">Table of n, a(n) for n=1..450</a>
%K nonn
%O 1,2
%A _R. H. Hardin_ Mar 13 2009