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A049888 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 2. 0

%I

%S 1,1,2,3,5,11,21,39,62,144,287,571,1126,2211,4197,7555,12039,28274,

%T 56547,113091,226166,452291,904357,1807875,3612679,7217516,14390524,

%U 28611429,56544667,110381012,209984179,377814215,602188918

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

%p end proc:

%p seq(a(n), n = 1..40); # _Petros Hadjicostas_, Nov 15 2019

%K nonn

%O 1,3

%A _Clark Kimberling_

%E Name edited by _Petros Hadjicostas_, Nov 15 2019

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Last modified November 29 10:22 EST 2021. Contains 349416 sequences. (Running on oeis4.)