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A217162
a(n) is the least value of k such that the decimal expansion of n^k contains seven consecutive identical digits.
3
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
2,1
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 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
V. Raman, Sep 27 2012
STATUS
approved