A049921 - OEIS

%I #11 Nov 14 2019 15:46:05

%S 1,3,2,3,8,14,29,57,116,176,380,775,1556,3117,6235,12469,24940,37412,

%T 81058,165234,332029,664839,1330073,2660350,5320760,10641579,21283186,

%U 42566387,85132780,170265565,340531131,681062261,1362124524

%N a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 2.

%p s := proc(n) option remember; `if`(n < 1, 0, a(n) + s(n - 1)) end proc:

%p a := proc(n) option remember;

%p `if`(n < 4, [1, 3, 2][n], s(n - 1) - a(2^ceil(log[2](n - 1)) + 2 - n)):

%p end proc:

%p seq(a(n), n = 1..34); # _Petros Hadjicostas_, Nov 14 2019

%K nonn

%O 1,2

%A _Clark Kimberling_

%E Name edited by _Petros Hadjicostas_, Nov 14 2019