A287388 Positions of 2 in A287385.

3, 4, 8, 11, 13, 18, 21, 23, 25, 30, 32, 34, 38, 40, 45, 48, 49, 53, 57, 58, 62, 66, 68, 70, 74, 76, 81, 84, 85, 89, 93, 95, 97, 101, 103, 108, 111, 113, 115, 119, 121, 126, 129, 130, 134, 138, 139, 143, 146, 148, 153, 156, 158, 160, 165, 166, 170, 173, 175

Offset: 1

Author

Clark Kimberling, May 25 2017

Keywords

• nonn
• easy

Comments

a(n) - a(n-1) is in {1,2,3,4,5} for n >= 1; also, 3n - a(n) is in {0,1,2} for n >= 1. The first 20 numbers 3n - a(n) are 0, 2, 1, 1, 2, 0, 0, 1, 2, 0, 1, 2, 1, 2, 0, 0, 2, 1, 0, 2, with 0 in positions given by A287386.

Links

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

Crossrefs

Cf. A287385, A287386, A287387.

Programs

Mathematica

s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 1, 0}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287385*)
Flatten[Position[s, 0]]; (*A287386*)
Flatten[Position[s, 1]]; (*A287387*)
Flatten[Position[s, 2]]; (*A287388*)