A372148 a(n) = A371764(n, 2).

1, 14, 86, 374, 1382, 4694, 15206, 47894, 148262, 453974, 1380326, 4177814, 12607142, 37968854, 114201446, 343194134, 1030762022, 3094645334, 9288654566, 27875400854, 83645076902, 250972979414, 752994435686, 2259134301974

Offset: 1

Author

Detlef Meya, Apr 20 2024

Keywords

• nonn
• easy

Links

• Paolo Xausa, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (6,-11,6).

Crossrefs

Cf. A371764.

Programs

Maple

a := n -> 2*(4*3^n - 9*2^n + 7) - `if`(n=1, 1, 0);
seq(a(n), n = 1..24);  # Peter Luschny, Apr 20 2024

Mathematica

A372148[n_] := 2*(4*3^n - 9*2^n + 7) - Boole[n == 1]; Array[A372148,50] (* or *)
LinearRecurrence[{6, -11, 6}, {1, 14, 86, 374}, 50] (* Paolo Xausa, May 25 2024 *)

Formula

a(n) = 2*(4*3^n - 9*2^n + 7) - [n = 1]. - Hugo Pfoertner, Apr 20 2024

G.f.: x*(1 + 8*x + 13*x^2 + 6*x^3)/((1 - x)*(1 - 2*x)*(1 - 3*x)). - Stefano Spezia, Apr 21 2024