A287522 Positions of 1 in A287520.

2, 4, 7, 10, 14, 16, 19, 22, 26, 28, 32, 34, 38, 40, 43, 46, 49, 53, 55, 59, 61, 64, 67, 71, 74, 76, 79, 82, 86, 88, 92, 94, 97, 100, 103, 107, 110, 112, 115, 118, 122, 124, 127, 130, 134, 136, 140, 142, 145, 148, 152, 155, 157, 160, 163, 167, 169, 173, 175

Offset: 1

Author

Clark Kimberling, May 30 2017

Keywords

• nonn
• easy

Comments

a(n) - a(n-1) is in {2, 3, 4} for n >= 1; also, 3n - a(n) is in {1, 2} for n >= 1. The first 20 numbers 3n - a(n) are 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 1, with 1 in positions given by A287521.

Links

• Clark Kimberling, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A287520, A287521, A189630.

Programs

Mathematica

s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 0, 2}, 2->{1, 2, 0}}] &, {0}, 9]; (*A287520*)
Flatten[Position[s, 0]]; (*A287521*)
Flatten[Position[s, 1]]; (*A287522*)
Flatten[Position[s, 2]]; (*A189630*)