A033499 - OEIS

A033499

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

1, 1, 3, 5, 9, 13, 19, 29, 41, 57, 79, 103, 137, 183, 233, 299, 387, 479, 595, 745, 901, 1103, 1355, 1617, 1945, 2361, 2789, 3309, 3945, 4597, 5399, 6357, 7337, 8519, 9953, 11411, 13131, 15179, 17261, 19759, 22685, 25657, 29149, 33277, 37455, 42285, 47917, 53615, 60271, 67907, 75631

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OFFSET

1,3

LINKS

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

MAPLE

A033499:= proc(n) option remember; if n <= 2 then 1 else A033499(n-1) + A033499(round(2*(n-1)/3)) + A033499(round((n-1)/3)); fi; end;

MATHEMATICA

a[n_]:= a[n]= If[n<3, 1, a[n-1] +a[Round[2*(n-1)/3]] +a[Round[(n-1)/3]]]; Table[a[n], {n, 55}] (* G. C. Greubel, Oct 14 2019 *)

PROG

(PARI) a(n) = if(n<3, 1, a(n-1)+a(round(2*(n-1)/3)) +a(round((n-1)/3)) );

vector(55, n, a(n) ) \\ G. C. Greubel, Oct 14 2019