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 A215236 Greatest integer k such that n^i has no identical consecutive digits for i = 0..k. 4

%I

%S 15,10,7,10,4,5,5,5,1,0,1,8,2,1,3,6,4,4,1,1,0,5,3,5,4,3,7,4,1,5,4,0,1,

%T 1,2,6,1,3,1,4,2,3,0,2,1,1,2,2,1,6,3,2,5,0,3,3,1,3,1,2,1,2,2,1,0,1,2,

%U 3,1,2,6,5,2,5,1,0,2,3,1,2,2,1,4,1,3,5,0

%N Greatest integer k such that n^i has no identical consecutive digits for i = 0..k.

%H T. D. Noe, <a href="/A215236/b215236.txt">Table of n, a(n) for n = 2..10000</a>

%F a(n) = A217157(n) - 1. - _Georg Fischer_, Nov 25 2020

%e a(2) = 15 because the powers of 2 are 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536 and only the 16th power has consecutive identical digits.

%t Table[k = 1; While[! MemberQ[Differences[IntegerDigits[n^k]], 0], k++]; k = k - 1, {n, 2, 100}]

%Y Cf. A216063 (highest power of n having different consecutive digits), A217157.

%K nonn,base

%O 2,1

%A _T. D. Noe_, Sep 17 2012

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Last modified August 7 15:47 EDT 2022. Contains 355994 sequences. (Running on oeis4.)