A287410 Positions of 2 in A287407.

3, 4, 7, 10, 13, 18, 19, 24, 25, 28, 33, 34, 37, 40, 45, 48, 49, 52, 55, 60, 61, 66, 67, 70, 73, 76, 81, 82, 87, 88, 93, 94, 97, 100, 103, 108, 109, 114, 115, 118, 121, 126, 129, 130, 133, 138, 139, 142, 145, 148, 153, 154, 159, 160, 163, 168, 169, 174, 175

Offset: 1

Author

Clark Kimberling, May 25 2017

Keywords

• nonn
• easy

Comments

a(n) - a(n-1) is in {1,3,5} for n >= 1; also, 3n - a(n) is in {0, 2} for n >= 1. The first 20 numbers 3n - a(n) are 0, 2, 2, 2, 2, 0, 2, 0, 2, 2, 0, 2, 2, 2, 0, 0, 2, 2, 2, 0, with 0 in positions given by A287408.

Links

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

Crossrefs

Cf. A287407, A287408, A287409.

Programs

Mathematica

s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 1, 0}, 2->{2, 0, 1}}] &, {0}, 9]; (*A287407*)
Flatten[Position[s, 0]]; (*A287408*)
Flatten[Position[s, 1]]; (*A287409*)
Flatten[Position[s, 2]]; (*A287410*)