A158141 Number of nondecreasing integer sequences of length 7 with sum zero and sum of absolute values 2n.

1, 4, 9, 24, 41, 87, 130, 234, 344, 542, 742, 1135, 1477, 2088, 2719, 3676, 4597, 6103, 7462, 9596, 11658, 14568, 17374, 21559, 25287, 30692, 35927, 42952, 49573, 58901, 67304, 78938, 89966, 104282, 117818, 136119, 152535, 174480, 195281, 221660

Offset

1,2

Comments

a(n) = A000041(n)^2 for n<=3

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

Links

R. H. Hardin, Table of n, a(n) for n=1..787

Crossrefs

Sequence in context: A286729 A159068 A255876 * A056575 A056032 A304908

Adjacent sequences: A158138 A158139 A158140 * A158142 A158143 A158144

Keyword

nonn

Author

R. H. Hardin Mar 13 2009

Status

approved