A217162 a(n) is the least value of k such that the decimal expansion of n^k contains seven consecutive identical digits.

972, 2124, 486, 2786, 1503, 1961, 324, 1062, 7, 1323, 1938, 512, 1053, 2600, 243, 2474, 1486, 940, 7, 1085, 1068, 238, 2908, 1393, 699, 708, 704, 1566, 7, 286, 1711, 935, 2225, 1190, 1357, 692, 1182, 448, 7, 885, 1349, 815, 647, 1675, 1131, 548, 333, 1154, 7

Offset: 2

Author

V. Raman, Sep 27 2012

Keywords

• nonn
• base

Links

• V. Raman, Table of n, a(n) for n = 2..1000

Crossrefs

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

Programs

Mathematica

Table[k = 1; While[! MemberQ[Partition[Differences[IntegerDigits[n^k]], 6, 1], {0, 0, 0, 0, 0, 0}], k++]; k, {n, 2, 100}] (* T. D. Noe, Oct 01 2012 *)
scd[n_]:=Module[{k=1},While[FreeQ[IntegerDigits[n^k],{_,x_,x_,x_,x_,x_,x_,x_,_}],k++];k]; Array[scd,50,2] (* Harvey P. Dale, May 23 2016 *)