A287564 Positions of 2 in A287561.

2, 8, 9, 15, 17, 23, 26, 32, 36, 37, 43, 46, 51, 54, 60, 61, 68, 69, 75, 78, 83, 86, 92, 93, 98, 104, 105, 111, 113, 119, 122, 128, 129, 135, 138, 144, 148, 149, 155, 158, 163, 166, 172, 173, 178, 184, 185, 191, 195, 198, 204, 205, 210, 216, 217, 223, 225

Offset: 1

Author

Clark Kimberling, May 31 2017

Keywords

• nonn
• easy

Comments

a(n) - a(n-1) is in {1,2,3,4,5,6,7} for n >= 1; also, 4n - a(n) is in {0,1,2,3} for n >= 1. The first 20 numbers 4n - a(n) are 2, 0, 3, 1, 3, 1, 2, 0, 0, 3, 1, 2, 1, 2, 0, 3, 0, 3, 1, 2, with

0 in positions given by A287564,

1 in positions given by A287565,

2 in positions given by A287562,

3 in positions given by A287563.

Links

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

Crossrefs

Cf. A287561, A287562, A287563, A287565.

Programs

Mathematica

s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9];   (* A287561 *)
Flatten[Position[s, 0]]; (* A287562 *)
Flatten[Position[s, 1]]; (* A287563 *)
Flatten[Position[s, 2]]; (* A287564 *)
Flatten[Position[s, 3]]; (* A287565 *)