A298341 a(n) = a(n-1) + a(n-2) + a([n/3]), where a(0) = 1, a(1) = 2, a(2) = 3.

1, 2, 3, 7, 12, 21, 36, 60, 99, 166, 272, 445, 729, 1186, 1927, 3134, 5082, 8237, 13355, 21628, 35019, 56707, 91786, 148553, 240438, 389090, 629627, 1018883, 1648676, 2667725, 4316673, 6984670, 11301615, 18286730, 29588790, 47875965, 77465484, 125342178

Offset: 0

Author

Clark Kimberling, Feb 09 2018

Keywords

• nonn
• easy

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Links

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

Crossrefs

Cf. A001622, A000045, A298338.

Programs

Mathematica

a[0] = 1; a[1] = 2; a[2] = 3;
a[n_] := a[n] = a[n - 1] + a[n - 2] + a[Floor[n/3]];
Table[a[n], {n, 0, 30}]  (* A298341 *)