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A070561
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a(0) = 0; for n > 0, a(n) = (fecundity of n) + 1.
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2
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0, 11, 10, 10, 9, 2, 9, 8, 8, 7, 1, 9, 8, 8, 7, 2, 7, 7, 6, 4, 1, 6, 6, 5, 6, 3, 5, 6, 3, 4, 1, 4, 5, 3, 3, 2, 4, 4, 4, 3, 1, 5, 2, 3, 2, 4, 2, 3, 2, 5, 1, 6, 4, 9, 3, 2, 5, 3, 3, 2, 1, 3, 3, 6, 6, 3, 2, 2, 8, 6, 1, 5, 5, 3, 2, 2, 7, 6, 4, 3, 1, 5, 3, 2, 8, 4, 4, 4, 5, 4, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Start with n, repeatedly replace x by x + product of digits of x until reach 0; fecundity = number of steps - 1.
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EXAMPLE
| 1 -> 2 -> 4 -> 8 -> 16 -> 22 -> 26 -> 38 -> 62 -> 74 ->102 -> 0 has fecundity 10.
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MATHEMATICA
| f[n_] := Length@FixedPointList[ # + Times @@ IntegerDigits@# &, n] - 1; f[0] = 0; Array[f, 105, 0] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 27 2010]
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CROSSREFS
| Cf. A070560. A070562, A031346, A003001.
Sequence in context: A055122 A004452 A112952 * A059941 A086100 A182782
Adjacent sequences: A070558 A070559 A070560 * A070562 A070563 A070564
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KEYWORD
| nonn,easy,base
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 07 2002
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 27 2010
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