A049976 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, 9, 21, 39, 81, 179, 418, 756, 1515, 3047, 6154, 12645, 26387, 57413, 135059, 243732, 487467, 974951, 1949962, 3900261, 7801619, 15607877, 31235987, 62580646, 125513700, 252489895, 510831447, 1045097262, 2184472237

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, 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: A092763 A232955 A116868 * A032789 A299123 A245455

Adjacent sequences: A049973 A049974 A049975 * A049977 A049978 A049979

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved