OFFSET
1,3
LINKS
Vladimir Kruchinin, The method for obtaining expressions for coefficients of reverse generating functions, arXiv:1211.3244 [math.CO], 2012.
FORMULA
a(n) = (Sum_{j=0..(n-1)/2} C(n-1-4*j,j)*C(2*n-4*j-2,n-1))/n.
MATHEMATICA
Table[Sum[Binomial[n-1-4*j, j]Binomial[2*n-4*j-2, n-1], {j, 0, (n-1)/2}]/n, {n, 1, 25}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Benedict W. J. Irwin, Sep 24 2016
STATUS
approved