A033498 a(n) = a(n-1)+ a(round(2*(n-1)/3)) +a(round((n-1)/3)) starting a(1)=1.

1, 3, 5, 9, 15, 23, 35, 53, 73, 101, 141, 185, 247, 329, 417, 533, 689, 853, 1061, 1331, 1613, 1977, 2429, 2899, 3485, 4227, 4989, 5915, 7049, 8211, 9643, 11357, 13111, 15229, 17799, 20413, 23497, 27167, 30899, 35373, 40609, 45927, 52171, 59549, 67015, 75643

Offset

1,2

Links

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

Maple

A033498 := proc(n) option remember; if n <= 1 then 1 else A033498(n-1)+A033498(round(2*(n-1)/3))+A033498(round((n-1)/3)); fi; end;

Mathematica

a[n_]:= a[n]= If[n<2, 1, 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<2, 1, 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 2 select 1 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<2): return 1
    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. A033499, A033500.

Sequence in context: A025207 A027688 A118403 * A147493 A178961 A147509

Adjacent sequences: A033495 A033496 A033497 * A033499 A033500 A033501

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Terms a(39) and onward added by G. C. Greubel, Oct 14 2019

Status

approved