A065360 Alternating sum of "negabits". Replace (-2)^k with (-1)^k in negabinary expansion of n.

1, 0, 1, 1, 2, -1, 0, 0, 1, 0, 1, 1, 2, 0, 1, 1, 2, 1, 2, 2, 3, -2, -1, -1, 0, -1, 0, 0, 1, -1, 0, 0, 1, 0, 1, 1, 2, -1, 0, 0, 1, 0, 1, 1, 2, 0, 1, 1, 2, 1, 2, 2, 3, -1, 0, 0, 1, 0, 1, 1, 2, 0, 1, 1, 2, 1, 2, 2, 3, 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, -3, -2, -2, -1, -2, -1, -1, 0, -2, -1, -1, 0, -1, 0, 0, 1, -2, -1, -1, 0, -1, 0, 0

Offset

1,5

Comments

Notation: (-2)[n](-1)

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

6 = 11010 -> +(1)-(1)+(0)-(1)+(0) = -1 = a(6).

Prog

(PARI) negab(n)=if(n, negab(n\(-2))*10+bittest(n, 0)); \\ A039724
a(n) = my(d=Vecrev(digits(negab(n)))); sum(k=1, #d, d[k]*(-1)^(k-1)); \\ Michel Marcus, Aug 28 2019

Crossrefs

Cf. A005351, A039724, A065359.

Sequence in context: A060564 A031267 A247763 * A352512 A364032 A333397

Adjacent sequences: A065357 A065358 A065359 * A065361 A065362 A065363

Keyword

base,easy,sign

Author

Marc LeBrun, Oct 31 2001

Status

approved