A049928 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) = 3, and a(3) = 4.

1, 3, 4, 7, 11, 25, 47, 87, 138, 322, 641, 1275, 2514, 4937, 9371, 16869, 26881, 63132, 126261, 252515, 504994, 1009897, 2019291, 4036709, 8066561, 16115612, 32131844, 63884955, 126255613, 246463956, 468862629, 843601489, 1344595962

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, 3, 4][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: A072255 A049863 A025068 * A002364 A042827 A041631

Adjacent sequences: A049925 A049926 A049927 * A049929 A049930 A049931

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved