A049921 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) = 3, and a(3) = 2.

1, 3, 2, 3, 8, 14, 29, 57, 116, 176, 380, 775, 1556, 3117, 6235, 12469, 24940, 37412, 81058, 165234, 332029, 664839, 1330073, 2660350, 5320760, 10641579, 21283186, 42566387, 85132780, 170265565, 340531131, 681062261, 1362124524

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 < 4, [1, 3, 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 14 2019

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019