OFFSET
0,3
COMMENTS
Hankel transform is (-1)^n*A128056(n).
FORMULA
a(n)=sum{k=0..n, sum{j=0..n, binomial(k-j,n-k-j)*binomial(k,j)*A000984(n-k-j)}}.
Conjecture: n*a(n) +(-2*n+1)*a(n-1) +5*(-n+1)*a(n-2) +3*(2*n-3)*a(n-3) +5*(n-2)*a(n-4)=0. - R. J. Mathar, Feb 13 2015
a(n) ~ ((1+sqrt(21))/2)^(n + 3/2) / (2 * 21^(1/4) * sqrt(Pi*n)) . - Vaclav Kotesovec, Oct 30 2017
MAPLE
A186335 := proc(n)
add(add(binomial(k-j, n-k-j)*binomial(k, j)*A000984(n-k-j), j=0..n), k=0..n) ;
end proc: # R. J. Mathar, Feb 13 2015
MATHEMATICA
Table[Sum[Sum[Binomial[k-j, n-k-j]*Binomial[k, j]*Binomial[2*(n-k-j), n-k-j], {j, 0, n}], {k, 0, n}], {n, 0, 40}] (* Vaclav Kotesovec, Oct 30 2017 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Feb 18 2011
STATUS
approved