A356248 Image of 1 under repeated application of the map k -> (2k-1,2k,2k-1).

1, 2, 1, 3, 4, 3, 1, 2, 1, 5, 6, 5, 7, 8, 7, 5, 6, 5, 1, 2, 1, 3, 4, 3, 1, 2, 1, 9, 10, 9, 11, 12, 11, 9, 10, 9, 13, 14, 13, 15, 16, 15, 13, 14, 13, 9, 10, 9, 11, 12, 11, 9, 10, 9, 1, 2, 1, 3, 4, 3, 1, 2, 1, 5, 6, 5, 7, 8, 7, 5, 6, 5, 1, 2, 1, 3, 4, 3, 1, 2, 1

Offset: 0

Author

Arie Bos, Jul 31 2022

Keywords

• nonn

Examples

			1 --> 1 2 1 --> 1 2 1 3 4 3 1 2 1 --> 1 2 1 3 4 3 1 2 1 5 6 5 7 8 7 5 6 5 1 2 1 3 4 3 1 2 1 -->...
		

Crossrefs

Cf. A289813.

Programs

PARI

a(n) = fromdigits(digits(n,3)%2,2) + 1; \\ Kevin Ryde, Jul 31 2022

Python

def aupton(terms):
    a, n = [1], 0
    while len(a) < 3*terms: a, n = a + [(1<Michael S. Branicky, Jul 31 2022

Formula

If A(n) = (a(0),a(1),...,a(3^n-1)), then A(n+1) = (A(n),2^n+A(n),A(n)).

a(n) = A289813(n) + 1. - Rémy Sigrist, Jul 31 2022