A049916 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) = 1.

1, 3, 1, 4, 8, 16, 32, 57, 90, 211, 422, 837, 1650, 3242, 6152, 11076, 17650, 41451, 82902, 165797, 331570, 663082, 1325832, 2650436, 5296370, 10581242, 21097232, 41945796, 82897330, 161824122, 307847382, 553894666, 882839280

Offset

1,2

Links

Table of n, a(n) for n=1..33.

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, 1][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: A025121 A025097 A122115 * A220605 A094166 A266131

Adjacent sequences: A049913 A049914 A049915 * A049917 A049918 A049919

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

Status

approved