login
A217161
a(n) is the least value of k such that the decimal expansion of n^k contains six consecutive identical digits.
3
971, 538, 486, 1087, 371, 175, 324, 269, 6, 482, 362, 327, 196, 516, 243, 350, 288, 144, 6, 895, 822, 238, 481, 1137, 281, 180, 127, 358, 6, 286, 454, 286, 347, 110, 481, 346, 314, 448, 6, 565, 388, 275, 90, 622, 231, 451, 37, 255, 6, 481, 202, 191, 472, 308
OFFSET
2,1
MATHEMATICA
Table[k = 1; While[! MemberQ[Partition[Differences[IntegerDigits[n^k]], 5, 1], {0, 0, 0, 0, 0}], k++]; k, {n, 2, 100}] (* T. D. Noe, Oct 01 2012 *)
lk[n_]:=Module[{k=1, t=Table[x_, 6]}, While[SequenceCount[IntegerDigits[ n^k], t]<1, k++]; k]; Array[lk, 60, 2] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 18 2018 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
V. Raman, Sep 27 2012
STATUS
approved