A120152 a(n) = 6 + floor((1 + Sum_{j=1..n-1} a(j))/3).

6, 8, 11, 14, 19, 25, 34, 45, 60, 80, 107, 142, 190, 253, 337, 450, 600, 800, 1066, 1422, 1896, 2528, 3370, 4494, 5992, 7989, 10652, 14203, 18937, 25249, 33666, 44888, 59850, 79800, 106400, 141867, 189156, 252208, 336277, 448370

Offset

1,1

Links

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

Mathematica

Module[{lista={6}}, Do[AppendTo[lista, Floor[(19+Total[lista])/3]], {40}]; lista] (* Harvey P. Dale, Jun 11 2013 *)
nxt[{s_, a_}]:=Module[{x=Floor[(19+s)/3]}, {s+x, x}]; NestList[nxt, {6, 6}, 40][[;; , 2]] (* Harvey P. Dale, Mar 26 2023 *)

Prog

(Magma)
function f(n, a, b)
  t:=0;
    for k in [1..n-1] do
      t+:= a+Floor((b+t)/3);
    end for;
  return t;
end function;
g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
A120152:= func< n | g(n, 6, 1) >;
[A120152(n): n in [1..60]]; // G. C. Greubel, Jun 15 2023
(SageMath)
@CachedFunction
def A120152(n): return 6 + (1 + sum(A120152(k) for k in range(1, n)))//3
[A120152(n) for n in range(1, 61)] # G. C. Greubel, Jun 15 2023

Crossrefs

Cf. A072493, A073941, A112088.

Sequence in context: A228650 A358531 A200722 * A315855 A287408 A287398

Adjacent sequences: A120149 A120150 A120151 * A120153 A120154 A120155

Keyword

nonn

Author

Graeme McRae, Jun 10 2006

Status

approved