A049892 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) = 3.

1, 1, 3, 4, 6, 14, 26, 49, 78, 181, 360, 717, 1414, 2776, 5270, 9486, 15116, 35501, 71000, 141997, 283974, 567896, 1135510, 2269966, 4536076, 9062306, 18068728, 35924482, 70997428, 138594290, 263655928, 474383156, 756107812

Offset

1,3

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, 1, 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: A180859 A271618 A137820 * A346504 A063477 A168219

Adjacent sequences: A049889 A049890 A049891 * A049893 A049894 A049895

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved