A120145 - OEIS

%I #7 May 14 2023 12:37:36

%S 20,30,45,68,102,153,229,344,516,774,1161,1741,2612,3918,5877,8815,

%T 13223,19834,29751,44627,66940,100410,150615,225923,338884,508326,

%U 762489,1143734,1715601,2573401,3860102,5790153,8685229,13027844

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

%H G. C. Greubel, <a href="/A120145/b120145.txt">Table of n, a(n) for n = 1..1000</a>

%t a[n_]:= a[n]= 20 +Quotient[1 +Sum[a[k], {k,n-1}], 2];

%t Table[a[n], {n,60}] (* _G. C. Greubel_, May 14 2023 *)

%o (SageMath)

%o @CachedFunction

%o def A120145(n): return 20 + (1+sum(A120145(k) for k in range(1,n)))//2

%o [A120145(n) for n in range(1,61)] # _G. C. Greubel_, May 14 2023

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

%K nonn

%O 1,1

%A _Graeme McRae_, Jun 10 2006