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A033500 a(n) = a(n-1) + a(round(2*(n-1)/3)) + a(round((n-1)/3)) with a(1)=1, a(2)=2. 3
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 (list; graph; refs; listen; history; text; internal format)
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: A175812 A002621 A343657 * A003318 A329398 A035300

Adjacent sequences:  A033497 A033498 A033499 * A033501 A033502 A033503

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 10 01:36 EDT 2021. Contains 343747 sequences. (Running on oeis4.)