A322780 First differences of A237262.

1, 4, 9, 32, 71, 252, 559, 1984, 4401, 15620, 34649, 122976, 272791, 968188, 2147679, 7622528, 16908641, 60012036, 133121449, 472473760, 1048062951, 3719778044, 8251382159, 29285750592, 64962994321, 230566226692, 511452572409, 1815244062944

Offset: 1

Author

N. J. A. Sloane, Jan 05 2019, following a suggestion from Stan Wagon

Keywords

• nonn
• easy

Links

• Colin Barker, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (0,8,0,-1).

Crossrefs

Cf. A237262, A199336.

Programs

PARI

Vec(x*(1 + 4*x + x^2) / (1 - 8*x^2 + x^4) + O(x^40)) \\ Colin Barker, Jan 06 2019

Formula

From Colin Barker, Jan 06 2019: (Start)

G.f.: x*(1 + 4*x + x^2) / (1 - 8*x^2 + x^4).

a(n) = 8*a(n-2) - a(n-4) for n>4.

(End)