A120145 a(n) = 20 + floor( (1 + Sum_{j=1..n-1} a(j)) / 2 ).

20, 30, 45, 68, 102, 153, 229, 344, 516, 774, 1161, 1741, 2612, 3918, 5877, 8815, 13223, 19834, 29751, 44627, 66940, 100410, 150615, 225923, 338884, 508326, 762489, 1143734, 1715601, 2573401, 3860102, 5790153, 8685229, 13027844

Offset

1,1

Links

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

Mathematica

a[n_]:= a[n]= 20 +Quotient[1 +Sum[a[k], {k, n-1}], 2];
Table[a[n], {n, 60}] (* G. C. Greubel, May 14 2023 *)

Prog

(SageMath)
@CachedFunction
def A120145(n): return 20 + (1+sum(A120145(k) for k in range(1, n)))//2
[A120145(n) for n in range(1, 61)] # G. C. Greubel, May 14 2023

Crossrefs

Cf. A073941, A072493, A112088, A120134 - A120144, A120146 - A120209.

Sequence in context: A108030 A095787 A198471 * A104048 A078499 A066027

Adjacent sequences: A120142 A120143 A120144 * A120146 A120147 A120148

Keyword

nonn

Author

Graeme McRae, Jun 10 2006

Status

approved