A081857 Jacobsthal sequence (A001045) as represented in base 4.

0, 1, 1, 3, 11, 23, 111, 223, 1111, 2223, 11111, 22223, 111111, 222223, 1111111, 2222223, 11111111, 22222223, 111111111, 222222223, 1111111111, 2222222223, 11111111111, 22222222223, 111111111111, 222222222223, 1111111111111

Offset

0,4

Links

Table of n, a(n) for n=0..26.

Eric Weisstein's World of Mathematics, Repunit.

Formula

For n > 0, a(2n) is represented as a string of n 1's and a(2n+1) as a string of (n-1) 2's followed by a 3.

Example

a(8)= 1111 because A001045(8)= 85 (in base 10) = 64 + 16 + 4 + 1 = 1 * (4^3) + 1 * (4^2) + 1 * (4^1) + 1.

Crossrefs

Cf. A002450.

Sequence in context: A158034 A002515 A096297 * A168163 A120088 A081737

Adjacent sequences: A081854 A081855 A081856 * A081858 A081859 A081860

Keyword

base,easy,nonn

Author

Matthew Vandermast, Apr 11 2003

Status

approved