A158164 - OEIS

%I #10 Oct 06 2025 11:24:17

%S 1,4,9,25,49,121,225,484,900,1764,3136,5929,10201,18225,30976,53358,

%T 88191,148151,239851,392395,625299,999124,1563656,2455480,3780743,

%U 5826519,8849597,13423122,20098272,30062630,44434404,65561648,95788280

%N Number of nondecreasing integer sequences of length 30 with sum zero and sum of absolute values 2n.

%H R. H. Hardin, <a href="/A158164/b158164.txt">Table of n, a(n) for n=1..238</a>

%F a(n) = A000041(n)^2 for n <= 15.

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

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 13 2009