A049901 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) = 2, and a(3) = 1.

1, 2, 1, 2, 5, 9, 19, 37, 75, 114, 246, 502, 1008, 2019, 4039, 8077, 16155, 24234, 52506, 107032, 215075, 430656, 861568, 1723268, 3446575, 6893188, 13786394, 27572798, 55145600, 110291203, 220582407, 441164813, 882329627, 1323494442

Offset

1,2

Links

Table of n, a(n) for n=1..34.

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, 1][n], s(n - 1) - a(2^ceil(log[2](n - 1)) + 2 - n)):
end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 14 2019

Crossrefs

Cf. A049885, A049893, A049913, A049917, A049921.

Sequence in context: A214899 A199599 A201163 * A117715 A330962 A327194

Adjacent sequences: A049898 A049899 A049900 * A049902 A049903 A049904

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

Status

approved