A006859 From paths in the plane. (Formerly M5210)

1, 30, 330, 2145, 10010, 37128, 116280, 319770, 793155, 1808950, 3848130, 7719075, 14725620, 26898080, 47303520, 80454132, 132835365, 213578430, 335304970, 515175045, 776173134, 1148670600, 1672307000, 2398236750, 3391791975, 4735616886, 6533333730, 8913805255

Offset

0,2

References

G. Kreweras and H. Niederhausen, Solution of an enumerative problem connected with lattice paths, European J. Combin., 2 (1981), 55-60.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=0..27.

Formula

G.f.: (1+x)(1 +19 x +56 x^2 +19 x^3 + x^4 ) / (1-x)^10.

a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)*(2*n+3)*(2*n+5)*(2*n+7)/15120. - Peter Bala, Oct 11 2011

Crossrefs

Sequence in context: A159543 A362521 A227689 * A341557 A107967 A354656

Adjacent sequences: A006856 A006857 A006858 * A006860 A006861 A006862

Keyword

nonn,easy

Author

Simon Plouffe

Status

approved