A158175 - OEIS

%I #10 Oct 08 2025 17:03:17

%S 1,4,9,25,49,121,225,484,900,1764,3136,5929,10201,18225,30976,53361,

%T 88209,148225,240100,393129,627263,1003996,1574987,2480486,3833330,

%U 5932881,9056968,13815957,20821892,31366853,46733017,69543060,102559313

%N Number of nondecreasing integer sequences of length 41 with sum zero and sum of absolute values 2n.

%H R. H. Hardin, <a href="/A158175/b158175.txt">Table of n, a(n) for n=1..204</a>

%F a(n) = A000041(n)^2 for n <= 20.

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

%Y Cf. A000041, A000712.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 13 2009