OFFSET
0,2
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Ira M. Gessel, Symmetric functions and P-recursiveness, J. Combin. Theory Ser. A 53 (1990), no. 2, 257-285.
FORMULA
a(n) = (1/36^n) * Sum_{i=0..2*n} binomial(2*n, i) * A000364(n+i).
MATHEMATICA
a[n_] := Sum[Binomial[2n, i]Abs[EulerE[2(n+i)]], {i, 0, 2n}]/36^n
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Edited by Dean Hickerson, Dec 10 2002
STATUS
approved