A217179 a(n) is the number of digits in the decimal representation of the smallest power of n that contains four consecutive identical digits.
13, 16, 55, 67, 90, 61, 55, 84, 5, 41, 20, 28, 17, 116, 55, 64, 98, 90, 6, 39, 57, 48, 57, 68, 63, 16, 31, 55, 6, 27, 55, 108, 53, 28, 100, 32, 62, 51, 7, 65, 33, 33, 74, 55, 55, 24, 61, 68, 7, 64, 73, 51, 68, 110, 42, 18, 46, 18, 8, 115, 27, 54, 55, 33, 31, 106
Offset: 2
Links
- V. Raman, Table of n, a(n) for n = 2..10000
Programs
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Mathematica
Table[k = 1; While[d = IntegerDigits[n^k]; ! MemberQ[Partition[Differences[d], 3, 1], {0, 0, 0}], k++]; Length[d], {n, 2, 100}] (* T. D. Noe, Oct 03 2012 *) ndsp[n_]:=Module[{k=1},While[SequenceCount[IntegerDigits[n^k],{x_,x_,x_,x_}] <1,k++];IntegerLength[n^k]]; Array[ndsp,70,2] (* Harvey P. Dale, Jul 01 2021 *)
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