A158173 Number of nondecreasing integer sequences of length 39 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, 240100, 393128, 627256, 1003966, 1574886, 2480191, 3832549, 5930964, 9052535, 13806201, 20801334, 31325111, 46651127, 69387131, 102270680

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..205

Formula

a(n) = A000041(n)^2 for n <= 19.

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: A158170 A158171 A158172 * A158174 A158175 A158176

Adjacent sequences: A158170 A158171 A158172 * A158174 A158175 A158176

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved