OFFSET
0,1
FORMULA
a(n)= sum(L(k+1)*L(n+4-k), k=0..n) = (11*n+7)*F(n+1)+7*(n+1)*F(n), with F(n) := A000045(n) (Fibonacci).
G.f.: (7+4*x)*(1+2*x)/(1-x-x^2)^2.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Feb 15 2002
STATUS
approved