A049908 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) = 1, a(2) = 2, and a(3) = 3.

1, 2, 3, 5, 8, 18, 34, 63, 100, 233, 464, 923, 1820, 3574, 6784, 12212, 19460, 45703, 91404, 182803, 365580, 731094, 1461824, 2922292, 5839620, 11666564, 23261184, 46248192, 91400140, 178422484, 339423404, 610707852, 973392440

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Maple

s := proc(n) option remember; `if`(n < 1, 0, a(n) + s(n - 1)) end proc:
a := proc(n) option remember; `if`(n < 4, [1, 2, 3][n],
       s(n - 1) - a(-2^ceil(log[2](n - 1)) + 2*n - 3))
     end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 15 2019

Crossrefs

Sequence in context: A205303 A025071 A319644 * A334535 A135568 A103004

Adjacent sequences: A049905 A049906 A049907 * A049909 A049910 A049911

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved