A049904 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 and a(2) = a(3) = 2.

1, 2, 2, 4, 7, 15, 29, 53, 84, 196, 391, 777, 1532, 3009, 5711, 10281, 16383, 38476, 76951, 153897, 307772, 615489, 1230671, 2460201, 4916223, 9821774, 19582980, 38935139, 76947379, 150209206, 285751655, 514138911, 819473546

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, 2][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: A049868 A120363 A118988 * A049906 A014265 A153967

Adjacent sequences: A049901 A049902 A049903 * A049905 A049906 A049907

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved