A287574 Positions of 2 in A287571.

4, 5, 11, 14, 18, 24, 25, 31, 33, 39, 42, 48, 51, 54, 60, 61, 67, 70, 76, 77, 84, 85, 91, 94, 98, 104, 105, 111, 113, 119, 122, 128, 130, 136, 137, 143, 145, 151, 154, 160, 163, 166, 172, 173, 180, 181, 187, 190, 193, 199, 202, 208, 211, 214, 220, 221, 228

Offset: 1

Author

Clark Kimberling, Jun 01 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 0, 3, 1, 2, 2, 0, 3, 1, 3, 1, 2, 0, 1, 2, 0, 3, 1, 2, 0, 3, with

0 in positions given by A287572,

1 in positions given by A287573,

2 in positions given by A287574,

3 in positions given by A287575.

Links

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

Crossrefs

Cf. A287571, A287572, A287573, A287575.

Programs

Mathematica

s = Nest[Flatten[# /. {0 -> {0,3,1,2}, 1 -> {3,1,2,0}, 2 -> {1,2,0,3}, 3 -> {2,0,3,1}}] &, {0}, 9];   (* A287571 *)
Flatten[Position[s, 0]]; (* A287572 *)
Flatten[Position[s, 1]]; (* A287573 *)
Flatten[Position[s, 2]]; (* A287574 *)
Flatten[Position[s, 3]]; (* A287575 *)

Formula

a(n) = 4n - A287571(n) for n >= 1.