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).
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
KEYWORD
nonn,easy
AUTHOR
STATUS
approved