A067981 Convolution of L(n+1) := A000204(n+1) (Lucas), n>=0, with L(n+3), n>=0.

4, 19, 48, 107, 220, 432, 822, 1529, 2796, 5045, 9006, 15936, 27992, 48863, 84840, 146623, 252368, 432816, 739914, 1261285, 2144484, 3637609, 6157218, 10401792, 17541100, 29531947, 49644192, 83336339

Offset: 0

Author

Wolfdieter Lang, Feb 15 2002

Keywords

• nonn
• easy

Comments

Third diagonal of triangle A067979. Third column of triangle A067990.

Formula

a(n)= sum(L(k+1)*L(n+3-k), k=0..n) = (7*n+4)*F(n+1)+4*(n+1)*F(n), with F(n) := A000045(n) (Fibonacci).

G.f.: (4+3*x)*(1+2*x)/(1-x-x^2)^2.