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A049905 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 3, where m = 2^(p+1) + 2 - n and p is the unique number such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 2. 1

%I

%S 1,2,2,3,7,12,25,50,101,153,331,675,1355,2714,5429,10858,21717,32577,

%T 70583,143881,289121,578922,1158188,2316554,4633160,9266371,18532767,

%U 37065547,74131099,148262202,296524405,593048810,1186097621

%N a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 3, where m = 2^(p+1) + 2 - n and p is the unique number such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 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 < 3, [1, 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 11 2019

%K nonn

%O 1,2

%A _Clark Kimberling_

%E Name edited by _Petros Hadjicostas_, Nov 11 2019

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Last modified April 14 22:47 EDT 2021. Contains 342971 sequences. (Running on oeis4.)