A212556 Representations of nonnegative integers in base -4: The range of A007608.

0, 1, 2, 3, 100, 101, 102, 103, 110, 111, 112, 113, 120, 121, 122, 123, 130, 131, 132, 133, 200, 201, 202, 203, 210, 211, 212, 213, 220, 221, 222, 223, 230, 231, 232, 233, 300, 301, 302, 303, 310, 311, 312, 313, 320, 321, 322, 323, 330, 331, 332, 333, 10000

Offset

1,3

Comments

Also: Numbers with an odd number of digits, using only digits 0 through 3.

(These numbers (or strings of digits) represent nonnegative integers in base -4, while the same type of numbers with an even number of digits represent negative numbers. See references in A007608 for more information.)

Links

Table of n, a(n) for n=1..53.

Prog

(PARI) {forstep(d=1, 3, 2, my(u=vector(d, i, 10^(d-i))~); forvec(v=vector(d, i, [i==1 & d>1, 3]), print1(v*u", ")))}
(PARI) is_A212556(n)==(#n=Str(n))%2 & !setminus(Set(Vec(n)), Vec("0123"))

Crossrefs

The same as A007608 sorted in increasing order.

Sequence in context: A208205 A128931 A323463 * A171460 A371120 A371270

Adjacent sequences: A212553 A212554 A212555 * A212557 A212558 A212559

Keyword

nonn,base

Author

M. F. Hasler, May 20 2012

Status

approved