A290916 a(n) = (1/8)*A290915(n).

0, 1, 4, 18, 84, 387, 1784, 8228, 37944, 174981, 806940, 3721270, 17160940, 79139079, 364956336, 1683025992, 7761412016, 35792386313, 165059516916, 761185462362, 3510269016516, 16187892672139, 74651791054120, 344262840164460, 1587596244438120

Offset: 0

Author

Clark Kimberling, Aug 18 2017

Keywords

• nonn
• easy

Links

• Clark Kimberling, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (4, 2, 4, -1)

Crossrefs

Cf. A000027, A290890, A290915.

Programs

Mathematica

z = 60; s = x/(1 - x)^2; p = 1 - 8 s^2;
Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290915 *)
u/8 (* A290916 *)

Formula

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

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

a(n) = (1/8)*A290915(n) for n >= 0.