A026601 Numbers k such that A026600(k) = 1.

1, 6, 8, 12, 14, 16, 20, 22, 27, 30, 32, 34, 38, 40, 45, 46, 51, 53, 56, 58, 63, 64, 69, 71, 75, 77, 79, 84, 86, 88, 92, 94, 99, 100, 105, 107, 110, 112, 117, 118, 123, 125, 129, 131, 133, 136, 141, 143, 147, 149, 151, 155, 157, 162

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

It appears that a(n) gives the position of its own n-th 1 modulo 3 term, the n-th 2 modulo 3 term in A026602, and the n-th multiple of 3 in A026603. A026602 and A026603 appear to have analogous indexical properties. - Matthew Vandermast, Oct 06 2010

This follows directly from the generating morphism for A026600: a 1 in position k creates a 1 in position 3k-2, a 2 in position 3k-1, and a 3 in position 3k. Since each block of three terms in A026600 is a permutation of {1,2,3}, these created terms are the k-th terms of their respective index sequences. The proof for the other index sequences is similar. - Charlie Neder, Mar 10 2019

Links

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

Crossrefs

Cf. A026600, A026602, A026603, A079498.

Formula

a(n) = A079498(n) + 1.