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A217160
a(n) is the least value of k such that the decimal expansion of n^k contains five consecutive identical digits.
3
220, 274, 110, 125, 226, 172, 105, 137, 5, 156, 40, 227, 196, 216, 55, 235, 78, 115, 5, 104, 133, 187, 126, 93, 115, 110, 21, 163, 5, 40, 44, 159, 104, 110, 113, 20, 200, 205, 5, 119, 142, 116, 90, 145, 156, 136, 37, 86, 5, 37, 62, 119, 85, 91, 107, 142, 40
OFFSET
2,1
MATHEMATICA
Table[k = 1; While[! MemberQ[Partition[Differences[IntegerDigits[n^k]], 4, 1], {0, 0, 0, 0}], k++]; k, {n, 2, 100}] (* T. D. Noe, Oct 01 2012 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
V. Raman, Sep 27 2012
STATUS
approved