A049905 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 3, where m = 2^(p+1) + 2 - n and p is the unique number such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 2.

1, 2, 2, 3, 7, 12, 25, 50, 101, 153, 331, 675, 1355, 2714, 5429, 10858, 21717, 32577, 70583, 143881, 289121, 578922, 1158188, 2316554, 4633160, 9266371, 18532767, 37065547, 74131099, 148262202, 296524405, 593048810, 1186097621

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Programs

Maple

s := proc(n) option remember; `if`(n < 1, 0, a(n) + s(n - 1)) end proc:
a := proc(n) option remember;
`if`(n < 3, [1, 2][n], s(n - 1) - a(2^ceil(log[2](n - 1)) + 2 - n)):
end proc:
seq(a(n), n = 1..34); # Petros Hadjicostas, Nov 11 2019

Extensions

Name edited by Petros Hadjicostas, Nov 11 2019