A049899 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 2 - 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) = 4.

1, 1, 4, 5, 6, 16, 28, 45, 61, 166, 328, 645, 1261, 2401, 4323, 6890, 9291, 25471, 50938, 101865, 203701, 407281, 814083, 1626410, 3248331, 6478081, 12879768, 25454120, 49689111, 94526551, 170077063, 271081695, 365608246, 1002298186

Offset

1,3

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, 1, 4][n], s(n - 1) - a(-2^ceil(log[2](n - 1)) + 2*n - 2)):
end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 19 2019

Crossrefs

Sequence in context: A050162 A345972 A224678 * A217464 A235711 A010753

Adjacent sequences: A049896 A049897 A049898 * A049900 A049901 A049902

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 19 2019

Status

approved