A018866 7^a(n) is smallest power of 7 beginning with n.

0, 4, 3, 2, 8, 14, 1, 7, 13, 45, 6, 38, 12, 57, 31, 5, 50, 37, 11, 69, 43, 30, 17, 4, 49, 36, 23, 10, 68, 55, 42, 29, 16, 3, 61, 48, 35, 106, 22, 9, 67, 138, 54, 41, 28, 99, 15, 228, 2, 60, 131, 47, 260, 34, 21, 92, 8, 150, 66, 137, 53, 195, 40, 182, 27, 98, 14, 85, 298, 72, 285

Offset

1,2

Links

D. Mondot, Table of n, a(n) for n=1..32699

Mathematica

With[{s=7^Range[0, 500]}, Flatten[Table[Position[s, _?(IntegerDigits[n] ==  Take[IntegerDigits[#], IntegerLength[n]]&), 1, 1], {n, 80}]]]-1//Quiet (* Harvey P. Dale, Feb 22 2018 *)

Crossrefs

Sequence in context: A371510 A258415 A132668 * A021235 A273991 A292828

Adjacent sequences: A018863 A018864 A018865 * A018867 A018868 A018869

Keyword

nonn,base

Author

David W. Wilson

Status

approved