A067980 Convolution of L(n+1) := A000204(n+1) (Lucas), n>=0, with L(n+2), n>=0.

3, 13, 31, 69, 140, 274, 519, 963, 1757, 3165, 5642, 9972, 17499, 30521, 52955, 91461, 157336, 269702, 460863, 785295, 1334713, 2263293, 3829846, 6468264, 10905075, 18355429, 30849559, 51776133, 86785892

Offset: 0

Author

Wolfdieter Lang, Feb 15 2002

Keywords

• nonn
• easy

Comments

Second diagonal of triangle A067979. Second column of triangle A067990.

Formula

a(n)= sum(L(k+1)*L(n+2-k), k=0..n) = (4*n+3)*F(n+1)+3*(n+1)*F(n), with F(n) := A000045(n) (Fibonacci).

G.f.: (3+x)*(1+2*x)/(1-x-x^2)^2.