A158171 Number of nondecreasing integer sequences of length 37 with sum zero and sum of absolute values 2n.

1, 4, 9, 25, 49, 121, 225, 484, 900, 1764, 3136, 5929, 10201, 18225, 30976, 53361, 88209, 148225, 240099, 393121, 627226, 1003865, 1574591, 2479410, 3830632, 5926533, 9042803, 13785729, 20759936, 31244179, 46497906, 69104776, 101763435

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..222

Formula

a(n) = A000041(n)^2 for n <= 18.

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

Crossrefs

Cf. A000041, A000712.

Sequence in context: A158168 A158169 A158170 * A158172 A158173 A158174

Adjacent sequences: A158168 A158169 A158170 * A158172 A158173 A158174

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved