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

Author

Graeme McRae, Jun 10 2006

Keywords

• nonn

Links

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

Crossrefs

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

Programs

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 *)

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