A287403 Positions of 1 in A287401.

2, 5, 7, 10, 14, 17, 20, 22, 26, 29, 31, 35, 37, 41, 44, 47, 50, 52, 55, 59, 62, 65, 67, 71, 74, 77, 79, 82, 86, 89, 92, 94, 98, 101, 104, 106, 110, 112, 116, 118, 122, 125, 128, 131, 133, 137, 140, 142, 145, 149, 152, 155, 157, 161, 164, 166, 170, 172, 176

Offset: 1

Author

Clark Kimberling, May 25 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, 1, 2, 2, 1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 1, 2, 2, 1, with 2 in positions given by A287404.

Links

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

Crossrefs

Cf. A287401, A189728, A287404.

Programs

Mathematica

s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 1, 0}, 2->{1, 2, 0}}] &, {0}, 9]; (*A287401*)
Flatten[Position[s, 0]]; (*A189728*)
Flatten[Position[s, 1]]; (*A287403*)
Flatten[Position[s, 2]]; (*A287404*)