A081857 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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.