A287559 - OEIS

%I #4 May 31 2017 16:14:38

%S 4,7,9,14,19,21,26,32,34,40,43,45,49,54,60,63,67,69,74,80,82,88,91,93,

%T 97,102,108,111,116,119,121,126,129,134,140,143,148,151,153,158,163,

%U 165,170,176,178,184,187,189,194,200,203,205,209,214,220,223,228

%N Positions of 2 in A287556.

%C 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, 1, 3, 2, 1, 3, 2, 0, 2, 0, 1, 3, 3, 2, 0, 1, 1, 3, 2, 0, with

%C 0 in positions given by A287557,

%C 1 in positions given by A287558,

%C 2 in positions given by A287560,

%C 3 in positions given by A287559.

%H Clark Kimberling, <a href="/A287559/b287559.txt">Table of n, a(n) for n = 1..10000</a>

%t s = Nest[Flatten[# /. {0 -> {0, 1, 3, 2}, 1 -> {1, 3, 2, 0}, 2 -> {3, 2, 0, 1}, 3 -> {2, 0, 1, 3}}] &, {0}, 9];   (* A287556 *)

%t Flatten[Position[s, 0]]; (* A287557 *)

%t Flatten[Position[s, 1]]; (* A287558 *)

%t Flatten[Position[s, 2]]; (* A287559 *)

%t Flatten[Position[s, 3]]; (* A287560 *)

%Y Cf. A287556, A287557, A287558, A287560.

%K nonn,easy

%O 1,1

%A _Clark Kimberling_, May 31 2017