A120143 a(n) = 17 + floor( (1 + Sum_{j=0..n-1} a(j))/2 ).

17, 26, 39, 58, 87, 131, 196, 294, 441, 662, 993, 1489, 2234, 3351, 5026, 7539, 11309, 16963, 25445, 38167, 57251, 85876, 128814, 193221, 289832, 434748, 652122, 978183, 1467274, 2200911, 3301367, 4952050, 7428075, 11142113, 16713169

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

nxt[{t_, a_}]:=Module[{c=17+Floor[(1+t)/2]}, {t+c, c}]; NestList[nxt, {17, 17}, 60][[All, 2]] (* Harvey P. Dale, Dec 25 2020 *)

Prog

(SageMath)
@CachedFunction
def A120143(n): return 17 + (1 +sum(A120143(k) for k in range(1, n)))//2
[A120143(n) for n in range(1, 60)] # G. C. Greubel, May 11 2023

Crossrefs

Cf. A073941, A072493, A112088, A120134 - A120142, A120144 - A120209.

Sequence in context: A171169 A316561 A034963 * A031204 A085051 A171954

Adjacent sequences: A120140 A120141 A120142 * A120144 A120145 A120146

Keyword

nonn

Author

Graeme McRae, Jun 10 2006

Status

approved