A074273 Positions in the Kolakoski sequence (A000002) where there are an even number of 1's and the current term is 1.

4, 7, 13, 16, 20, 23, 28, 31, 34, 40, 43, 48, 51, 55, 59, 64, 68, 71, 76, 79, 85, 88, 94, 97, 101, 104, 109, 113, 116, 121, 124, 128, 131, 134, 140, 143, 148, 152, 157, 160, 164, 168, 173, 176, 179, 184, 187, 191, 194, 199, 202, 208, 211, 217, 220, 223, 227

Offset

1,1

Comments

n such that A000002(n) = 1 and A000002(m) = 1 for an even number of indices m <= n.

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Example

The Kolakoski sequence begins 1,2,2,1,1,2,1,2,2,1,2,2,1,1,... Therefore at positions 4, 7 and 13 we have 2,4 and 6 1's in the sequence.

Crossrefs

Cf. A074274, A074278.

Sequence in context: A045090 A213382 A258867 * A310801 A310802 A310803

Adjacent sequences: A074270 A074271 A074272 * A074274 A074275 A074276

Keyword

nonn,easy

Author

Jon Perry, Sep 21 2002

Extensions

Edited and extended by Nathaniel Johnston, May 02 2011

Status

approved