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A060630 a(n) gives smallest number requiring n iterations of the map i -> A053392(i) to reach zero. 2
0, 1, 10, 19, 109, 149, 197, 399, 694, 796, 893, 897, 1167, 1579, 1596, 1667, 1790, 1777, 2859, 1779, 1778, 1873, 3679, 5926, 11289, 9539, 13551, 4589, 5960, 12066, 12265, 19119, 10927, 12379, 11742, 65220, 34038, 40390, 1110025, 10100023 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

24th and 26th terms are unknown, but a(25)=9539, a(27)=4589 and a(28)=5960.

LINKS

Table of n, a(n) for n=0..39.

Erich Friedman, Problem of the Month (Feb 2000)

FORMULA

a(n)=10^(n-2)+9, for n=2, 3, 4 and for n > 40.

EXAMPLE

a(5)=149 because 149 -(1)-> 513 -(2)-> 64 -(3)-> 10 -(4)-> 1 -(5)-> 0. a(7)=399 because 399 -(1)-> 1218 -(2)-> 339 -(3)-> 612 -(4)-> 73 -(5)-> 10 -(6)-> 1 -(7)-> 0.

CROSSREFS

Cf. A053392.

Sequence in context: A219688 A166706 A131495 * A070199 A015445 A220005

Adjacent sequences:  A060627 A060628 A060629 * A060631 A060632 A060633

KEYWORD

base,nonn

AUTHOR

Jason Earls, Apr 14 2001

EXTENSIONS

More terms from Berend Jan van der Zwaag, Jun 23 2001

STATUS

approved

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Last modified September 16 10:58 EDT 2019. Contains 327095 sequences. (Running on oeis4.)