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`%I #4 May 31 2017 15:47:03
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`%S 4,7,10,13,19,22,25,32,34,37,44,47,49,56,59,62,67,70,73,80,82,85,92,
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`%T 95,97,104,107,110,116,119,122,125,130,133,140,143,145,152,155,158,
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`%U 164,167,170,173,179,182,185,192,193,200,203,206,212,215,218,221,227
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`%N Positions of 3 in A053839.
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`%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, 2, 3, 1, 2, 3, 0, 2, 3, 0, 1, 3, 0, 1, 2, 1, 2, 3, 0, with
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`%C 0 in positions given by A287552,
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`%C 1 in positions given by A287553,
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`%C 2 in positions given by A287554,
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`%C 3 in positions given by A287555.
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`%H Clark Kimberling, <a href="/A287555/b287555.txt">Table of n, a(n) for n = 1..10000</a>
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`%t s = Nest[Flatten[# /. {0 -> {0, 1, 2, 3}, 1 -> {1, 2, 3, 0}, 2 -> {2, 3, 0, 1}, 3 -> {3, 0, 1, 2}}] &, {0}, 9]; (* A053839 *)
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`%t Flatten[Position[s, 0]]; (* A287552 *)
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`%t Flatten[Position[s, 1]]; (* A287553 *)
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`%t Flatten[Position[s, 2]]; (* A287554 *)
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`%t Flatten[Position[s, 3]]; (* A287555 *)
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`%Y Cf. A053839, A287552, A287553, A287554.
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`%K nonn,easy
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`%O 1,1
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`%A _Clark Kimberling_, May 31 2017
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