A217163 a(n) is the least value of k such that the decimal expansion of n^k contains eight or more consecutive identical digits.

8554, 7720, 4277, 2790, 8533, 6176, 4442, 3860, 8, 2983, 2430, 5482, 1053, 5030, 3502, 5781, 3982, 4706, 8, 2568, 4850, 2740, 4549, 1395, 699, 2960, 2679, 3197, 8, 4057, 2709, 3115, 3436, 1190, 6629, 692, 3274, 5773, 8, 6997, 3536, 5936, 647, 3204, 1369, 1587

Offset

2,1

Links

V. Raman, Table of n, a(n) for n = 2..100

Mathematica

Table[k = 1; While[! MemberQ[Partition[Differences[IntegerDigits[n^k]], 7, 1], {0, 0, 0, 0, 0, 0, 0}], k++]; k, {n, 2, 50}] (* T. D. Noe, Oct 01 2012 *)
lvk8[n_]:=Module[{k=Ceiling[Log[n, 11111111]]}, While[Max[Length/@ Split[ IntegerDigits[n^k]]]<8, k++]; k] Array[lvk8, 50, 2] (* Harvey P. Dale, Jul 31 2013 *)

Crossrefs

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

Sequence in context: A202986 A297896 A217338 * A243839 A287119 A156846

Adjacent sequences: A217160 A217161 A217162 * A217164 A217165 A217166

Keyword

nonn,base

Author

V. Raman, Sep 27 2012

Extensions

Definition clarified by Harvey P. Dale, Jul 31 2013

Status

approved