

A075000


Smallest number such that n*a(n) is a concatenation of n consecutive integers; or 0 if no such number exists.


13



1, 6, 41, 864, 2469, 20576, 493827, 7098637639, 13717421, 1234567891, 82737383012865106529, 10288065758426, 3513762316247164732, 563643651522439401227280, 8230452606740808761
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OFFSET

1,2


COMMENTS

Conjecture: For every n there exists a nonzero a(n).


LINKS

Robert G. Wilson v, Table of n, a(n) for n = 0..100.


FORMULA

a(n) = A077306(n)/n. [Amarnath Murthy, Nov 03 2002]


EXAMPLE

a(11) = 82737383012865106529 as 11*82737383012865106529 = 910111213141516171819 is the concatenation of 11 numbers from 9 to 19.


MATHEMATICA

f[ n_ ] := Block[ {id = Range@n}, While[ k = FromDigits@ Flatten@ IntegerDigits@ id/n; !IntegerQ@k, id++ ]; k ]; Array[ f, 16 ]  Robert G. Wilson v, Oct 19 2007


CROSSREFS

Cf. A074991, A074992, A074993, A074994, A074995, A074996, A036377, A073086, A074999, A075001.
Sequence in context: A167588 A230134 A007130 * A112960 A181041 A109856
Adjacent sequences: A074997 A074998 A074999 * A075001 A075002 A075003


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Aug 31 2002


EXTENSIONS

More terms from Rick L. Shepherd, Sep 03 2002


STATUS

approved



