A217160 a(n) is the least value of k such that the decimal expansion of n^k contains five consecutive identical digits.

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

Author

V. Raman, Sep 27 2012

Keywords

• nonn
• base

Links

• V. Raman, Table of n, a(n) for n = 2..10000

Crossrefs

Cf. A045875, A215727, A215728, A215729, A215730, A215731.

Programs

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 *)