A093969 a(n) = n*Pell(n-2).

0, 1, 0, 3, 8, 25, 72, 203, 560, 1521, 4080, 10835, 28536, 74633, 194040, 501915, 1292512, 3315425, 8474976, 21597091, 54884200, 139127289, 351877416, 888121195, 2237336592, 5626467025, 14126832720, 35416929267, 88670846936

Offset: 0

Author

Paul Barry, Apr 21 2004

Keywords

• easy
• nonn

Comments

The signed version (-1)^(n+1)*n*Pell(n-2) is the second inverse binomial transform of A093967.

Links

• Index entries for linear recurrences with constant coefficients, signature (4,-2,-4,-1).

Crossrefs

Cf. A000129.

Formula

G.f.: x(1-4x+5x^2)/(1-2x-x^2)^2;

a(n) = n*(1 + sqrt(2))^n*(3*sqrt(2)/4 - 1) - n*(1 - sqrt(2))^n*(3*sqrt(2)/4 + 1).