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A188195
Base-3 Keith numbers.
8
3, 5, 6, 7, 57, 102, 127, 206, 217, 677, 805, 840, 1486, 1680, 1887, 2090, 2834, 8329, 10145, 12866, 21127, 23002, 50782, 67925, 82685, 96841, 153861, 178852, 357896, 3826652, 17985694, 38610616, 38610808, 70587766, 160804168, 341014432, 632582224
OFFSET
1,1
COMMENTS
Keith numbers are described in A007629.
EXAMPLE
57 is here because, in base 3, 57 is 2010 and applying the Keith iteration to this number produces the numbers 2, 0, 1, 0, 3, 4, 8, 15, 30, 57.
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[#, 3]&]
CROSSREFS
Cf. A007629 (base 10), A162724 (base 2), A187713 (base 5), A188196-A188200.
Sequence in context: A179220 A290577 A145736 * A337092 A021741 A201906
KEYWORD
nonn,base
AUTHOR
T. D. Noe, Mar 24 2011
STATUS
approved