

A098143


Largest concatenation obtained by appending successively to n the least digit that forms a continuous succession of kdigit multiples of k, k=1,2,3,....


0



10200056405, 20120456708436008, 3000004020247, 4020002460123, 501204240024885, 60000016505, 702000648036, 8012046420482, 9000005670721808, 10200056405, 11, 1200003210, 13, 1412040060249008, 15, 1620003240960, 17, 1800001620, 19, 20120456708436008
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..20.


FORMULA

In the sequence, a(5)=501204240024885 and a(14)=1412040060249008 because we respectively have 15, 250, 3501, 45012, ..., 15501204240024885 and 11, 214, 3141, ..., 161412040060249008 when the process halts.


EXAMPLE

To get a(1): appending 0 to 1 gives 10 which is a multiple of 2.
Appending a 2 to 10 gives 102 which is a multiple of 3.
Appending a 0 to 102 gives 1020 which is a multiple of 4.
Appending a 0 to 1020 gives 10200 which is a multiple of 5.
...
Appending a 5 to 1020005640 gives 10200056405 which is a multiple of 11.
But now there is no digit x which makes 10200056405x a multiple of 12, so we stop, with a(1) = 10200056405.  N. J. A. Sloane, Nov 05 2016


CROSSREFS

Sequence in context: A159569 A159292 A144648 * A276590 A259152 A135047
Adjacent sequences: A098140 A098141 A098142 * A098144 A098145 A098146


KEYWORD

nonn,base


AUTHOR

Lekraj Beedassy, Sep 28 2004


EXTENSIONS

a(1), a(3) and a(11) corrected and a(15)a(20) added from Seiichi Manyama, Oct 04 2016


STATUS

approved



