A158177 Number of nondecreasing integer sequences of length 43 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, 393129, 627264, 1004003, 1575017, 2480587, 3833625, 5933662, 9058885, 13820392, 20831658, 31387475, 46774967, 69625674, 102717148

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..199

Formula

a(n) = A000041(n)^2 for n <= 21.

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: A158174 A158175 A158176 * A158178 A158179 A158180

Adjacent sequences: A158174 A158175 A158176 * A158178 A158179 A158180

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved