A298417 a(n) = 2*a(n-1) + 2*a(n-2) + a([n/2]), where a(0) = 1, a(1) = 1, a(2) = 1.

1, 1, 1, 5, 13, 37, 105, 289, 801, 2193, 6025, 16473, 45101, 123253, 336997, 920789, 2516373, 6875125, 18785189, 51322821, 140222045, 383095757, 1046652077, 2859512141, 7812373537, 21343816457, 58312503241, 159312762649, 435250868777, 1189127599849

Offset

0,4

Comments

a(n)/a(n-1) -> 1+sqrt(3).

Links

Clark Kimberling, Table of n, a(n) for n = 0..1000

Mathematica

a[0] = 1; a[1] = 1; a[2] = 1;
a[n_] := a[n] = 2 a[n - 1] + 2 a[n - 2] + a[Floor[n/2]];
Table[a[n], {n, 0, 30}]  (* A298417 *)

Crossrefs

Cf. A298338, A298416.

Sequence in context: A083413 A232879 A269803 * A193642 A220709 A182312

Adjacent sequences: A298414 A298415 A298416 * A298418 A298419 A298420

Keyword

nonn,easy

Author

Clark Kimberling, Feb 11 2018

Status

approved