A049973 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 and a(2) = a(3) = 3.

1, 3, 3, 10, 18, 45, 83, 166, 330, 825, 1567, 3096, 6165, 12322, 24637, 49274, 98546, 246365, 468093, 923871, 1841585, 3680101, 7358673, 14716604, 29432713, 58865262, 117730441, 235460844, 470921661, 941843314, 1883686621

Offset

1,2

Links

Table of n, a(n) for n=1..31.

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, 3][n], s(n - 1) + a(2^ceil(log[2](n - 1)) + 2 - n)):
end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 14 2019

Crossrefs

Cf. A049933, A049937, A049945.

Sequence in context: A024313 A132331 A077899 * A025519 A360651 A076987

Adjacent sequences: A049970 A049971 A049972 * A049974 A049975 A049976

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

Status

approved