A033500 a(n) = a(n-1) + a(round(2*(n-1)/3)) + a(round((n-1)/3)) with a(1)=1, a(2)=2.

1, 2, 4, 7, 12, 18, 27, 41, 57, 79, 110, 144, 192, 256, 325, 416, 538, 666, 828, 1038, 1257, 1540, 1892, 2258, 2715, 3294, 3889, 4612, 5497, 6404, 7521, 8857, 10224, 11874, 13876, 15912, 18314, 21173, 24080

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Maple

A033500 := proc(n) option remember; if n <= 2 then n else A033500(n-1)+A033500(round(2*(n-1)/3))+A033500(round((n-1)/3)); fi; end;

Mathematica

a[n_]:= a[n]= If[n<3, n, a[n-1] +a[Round[2*(n-1)/3]] +a[Round[(n-1)/3]]];
Table[a[n], {n, 50}] (* G. C. Greubel, Oct 14 2019 *)

Prog

(PARI) a(n) = if(n<3, n, a(n-1)+a(round(2*(n-1)/3)) +a(round((n-1)/3)) );
vector(50, n, a(n) ) \\ G. C. Greubel, Oct 14 2019
(Magma) a:= func< n | n lt 3 select n else Self(n-1) + Self(Round(2*(n-1)/3)) + Self(Round((n-1)/3)) >;
[a(n): n in [1..50]]; // G. C. Greubel, Oct 14 2019
(Sage)
@CachedFunction
def a(n):
    if (n<3): return n
    else: return a(n-1) +a(round(2*(n-1)/3)) +a(round((n-1)/3))
[a(n) for n in (1..50)] # G. C. Greubel, Oct 14 2019

Crossrefs

Cf. A033498, A033499.

Sequence in context: A002621 A343657 A363211 * A003318 A329398 A353150

Adjacent sequences: A033497 A033498 A033499 * A033501 A033502 A033503

Keyword

nonn

Author

N. J. A. Sloane

Status

approved