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A277149 Lexicographically least sequence of nonnegative integers that avoids 9/5-powers. 4

%I #9 Nov 08 2016 20:23:43

%S 0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,

%T 1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,

%U 0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,2,0,0,0

%N Lexicographically least sequence of nonnegative integers that avoids 9/5-powers.

%C This sequence is 13-regular.

%C More generally, if a/b is a rational number in the interval 5/3 <= a/b < 2 with gcd(b, 2) = 1 and gcd(a, b) = 1, then the lexicographically least sequence of nonnegative integers that avoids a/b-powers is (2 a - b)-regular.

%H Eric Rowland, <a href="/A277149/b277149.txt">Table of n, a(n) for n = 0..20000</a>

%H Lara Pudwell and Eric Rowland, <a href="http://arxiv.org/abs/1510.02807">Avoiding fractional powers over the natural numbers</a>, arXiv:1510.02807 [math.CO] (2015).

%F a(13 n + 12) = a(n) + 1.

%t (* This gives the first 2197 terms. *)

%t SubstitutionSystem[{n_ :> {0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, n + 1}}, {0}, {{3}}]

%Y Cf. A277143, A277156, A277157 (sequences in the same family).

%K nonn

%O 0,117

%A _Eric Rowland_, Oct 01 2016

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Last modified May 6 09:39 EDT 2024. Contains 372293 sequences. (Running on oeis4.)