A158174 Number of nondecreasing integer sequences of length 40 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, 627261, 1003986, 1574951, 2480376, 3833030, 5932129, 9055198, 13812005, 20813458, 31349531, 46698673, 69477026, 102435971

Offset

1,2

Links

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

Formula

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

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: A158171 A158172 A158173 * A158175 A158176 A158177

Adjacent sequences: A158171 A158172 A158173 * A158175 A158176 A158177

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved