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A097156 Least number that requires exactly n iterations of f(x) = reverse(x) - maxdigit(x) to reach zero. 5
1, 11, 16, 12, 15, 25, 36, 106, 104, 108, 197, 1009, 1022, 1052, 1091, 1073, 1801, 10004, 10005, 10051, 10062, 10071, 10083, 10081, 10092, 14991, 19982, 19991, 100092, 100192, 100282, 100191, 107991, 101973, 289101, 1000094, 1000084 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..37.

EXAMPLE

a(5)=15 because 15 -> 46 -> 58 -> 77 -> 70 -> 0 takes five steps to reach zero.

MATHEMATICA

g[n_] := Block[{id = IntegerDigits[n]}, ie = FromDigits[ Reverse[id]] - Union[id][[ -1]]; If[ie == 89, 0, ie]]; h[n_] := Length[NestWhileList[g, n, UnsameQ, All]] - 2; Do[ a = h[n]; If[a < 51 && t[[a]] == 0, t[[a]] = n], {n, 10^6}] (* Robert G. Wilson v, Aug 13 2004 *)

CROSSREFS

Cf. A097153, A097154, A097155, A097157, A097158.

Sequence in context: A147339 A147377 A147333 * A138791 A132990 A074197

Adjacent sequences:  A097153 A097154 A097155 * A097157 A097158 A097159

KEYWORD

base,nonn

AUTHOR

Jason Earls, Aug 01 2004

EXTENSIONS

More terms from Robert G. Wilson v, Aug 13 2004

STATUS

approved

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Last modified October 20 03:04 EDT 2021. Contains 348099 sequences. (Running on oeis4.)