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A097155
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Numbers that reach the fixed point 89 under iteration of f(x) = reverse(x) - maxdigit(x).
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5
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89, 890, 998, 2125, 3126, 5207, 6207, 7018, 7019, 8099, 8900, 9098, 9899, 9980, 10151, 10152, 10224, 12205, 12259, 12268, 14085, 14086, 15095, 15096, 17972, 18971, 21250, 22015, 22269, 23077, 24005, 24086, 24087, 25096, 26963, 27962
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 89 is the first number that will not reach zero under iteration of f(x) = reverse(x) - maxdigit(x), since 98-9=89. It is conjectured that 0 and 89 are the only fixed points of f.
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EXAMPLE
| a(5)=3126 because 3126 -> 6207 -> 7019 -> 9098 -> 8900 -> 89.
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MATHEMATICA
| nxt[n_]:=Module[{ridn=Reverse[IntegerDigits[n]]}, FromDigits[ridn]- Max[ ridn]]; Transpose[Select[Table[{i, NestWhile[nxt, i, !MemberQ[{0, 89}, #]&]}, {i, 30000}], #[[2]]==89&]][[1]] (* From Harvey P. Dale, Dec 21 2011 *)
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CROSSREFS
| Cf. A097153, A097154, A097156, A097157, A097158.
Sequence in context: A069764 A053580 A103548 * A197348 A158716 A093289
Adjacent sequences: A097152 A097153 A097154 * A097156 A097157 A097158
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KEYWORD
| base,easy,nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Aug 01 2004
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EXTENSIONS
| Corrected by Harvey P. Dale, Dec 21 2011
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