A098143 Largest concatenation obtained by appending successively to n the least digit that forms a continuous succession of k-digit multiples of k, k=1,2,3,....

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

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 1|5, 2|50, 3|501, 4|5012, ..., 15|501204240024885 and 1|1, 2|14, 3|141, ..., 16|1412040060249008 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 A371361

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