A290910 a(n) = (1/5)*A290909(n), n>= 0.

0, 1, 4, 15, 60, 240, 956, 3809, 15180, 60495, 241080, 960736, 3828664, 15257745, 60804180, 242312895, 965649716, 3848244944, 15335777460, 61115150865, 243552156060, 970588338271, 3867926023024, 15414209227200, 61427712082800, 244797754857825

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, -1, 4, -1)

Crossrefs

Cf. A000027, A290890, A290909.

Programs

Mathematica

z = 60; s = x/(1 - x)^2; p = 1 - 5 s^2;
Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290909 *)
u/5 (* A290910 *)
LinearRecurrence[{4,-1,4,-1},{0,1,4,15},30] (* Harvey P. Dale, Feb 19 2018 *)

PARI

concat([0], Vec(1/(1 - 4*x + x^2 - 4*x^3 + x^4) + O(x^30))) \\ Andrew Howroyd, Feb 26 2018

Formula

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

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

a(n) = (1/5)*A290909(n) for n >= 0.