A049955 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) = 1 and a(2) = a(3) = 2.

1, 2, 2, 7, 19, 33, 71, 168, 471, 776, 1557, 3140, 6415, 13438, 29240, 68778, 192896, 317016, 634037, 1268100, 2536335, 5073278, 10148920, 20308138, 40671616, 81591470, 164134024, 332073226, 679381312, 1420045956, 3090573668

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, 2, 2][n], s(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 2)); end proc:
seq(a(n), n = 1 .. 40); # Petros Hadjicostas, Apr 23 2020

Crossrefs

Cf. A049906 (similar, but with minus a(m/2)), A049907 (similar, but with minus a(m)), A049954 (similar, but with plus a(m/2)).

Sequence in context: A203579 A338415 A243022 * A184714 A156464 A156520

Adjacent sequences: A049952 A049953 A049954 * A049956 A049957 A049958

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Apr 23 2020

Status

approved