A333906 For n >= 2, a(n) = Sum_{k=2..n} prevpower2(k) + nextpower2(k) - 2*k, where prevpower2(k) is the largest power of 2 < k, nextpower2(k) is the smallest power of 2 > k.

1, 1, 3, 5, 5, 3, 7, 13, 17, 19, 19, 17, 13, 7, 15, 29, 41, 51, 59, 65, 69, 71, 71, 69, 65, 59, 51, 41, 29, 15, 31, 61, 89, 115, 139, 161, 181, 199, 215, 229, 241, 251, 259, 265, 269, 271, 271, 269, 265, 259, 251, 241, 229, 215, 199, 181, 161

Offset

2,3

Comments

Partial sums of b(k) = prevpower2(k) + nextpower2(k) - 2*k; b(k) = 0 for A007283.

Links

Table of n, a(n) for n=2..58.

Example

a(2) = (1 + 4 - 2*2) = 1;
a(3) = (1 + 4 - 2*2) + (2 + 4 - 2*3) = 1;
a(4) = (1 + 4 - 2*2) + (2 + 4 - 2*3) + (2 + 8 - 2*4) = 3.

Crossrefs

Cf. A000079, A007283, A062050, A080079.

Sequence in context: A184593 A328154 A249304 * A306224 A189202 A153098

Adjacent sequences: A333903 A333904 A333905 * A333907 A333908 A333909

Keyword

nonn

Author

Ctibor O. Zizka, Apr 09 2020

Status

approved