A188198 Base-7 Keith numbers.

8, 13, 16, 19, 24, 32, 40, 48, 57, 114, 125, 145, 171, 228, 285, 329, 342, 589, 1969, 2833, 4938, 30318, 43153, 168516, 336774, 375008, 652933, 1068018, 2955098, 5658387, 11096232, 19623430, 26245925, 81805113, 112442958, 119572340, 130712398, 407198006, 494835656, 508871625, 564319261, 712864110

Offset

1,1

Comments

Keith numbers are described in A007629.

Links

Amiram Eldar, Table of n, a(n) for n = 1..53

Example

48 is here because, in base 7, 48 is 66 and applying the Keith iteration to this number produces the numbers 6, 6, 12, 18, 30, 48.

Mathematica

IsKeith[n_, b_] := Module[{d, s, k}, d = IntegerDigits[n, b]; s = Total[d]; k = 1; While[AppendTo[d, s]; s = 2 s - d[[k]]; s < n, k++]; s == n]; Select[Range[3, 10^5], IsKeith[#, 7]&]

Crossrefs

Cf. A007629 (base 10), A162724 (base 2), A187713 (base 5), A188195-A188200 (bases 3-4 and 6-9).

Sequence in context: A287159 A272486 A057486 * A129410 A338598 A168339

Adjacent sequences: A188195 A188196 A188197 * A188199 A188200 A188201

Keyword

nonn,base

Author

T. D. Noe, Mar 24 2011

Status

approved