A088799 Numbers n which are divisors of the number formed by concatenating (n-3), (n-2) and (n-1) in that order.

3, 11, 9491, 12258083, 36774249, 2159487563, 2561252691, 2723957777, 6478462689, 8171873331, 333351714587, 146217070005379, 438651210016137, 13919982618156833, 41759947854470499, 1278907806311980217974478364841

Offset

1,1

Comments

Apart from 11, each other term in this sequence appears to also be a factor of the number formed by concatenating (n+3), (n+2) and (n+1) in that order. All terms appear to be prime. When evaluating concat((n+3),(n+2),(n+1)) - concat((n-3),(n-2),(n-1)) for members larger than 11 the difference appears to always be a number of the form 6(0)...4(0)...2 with the same number of zeros on both sides of the 4. The member will be a prime factor of this number. By factoring numbers of the form 6(0)...4(0)...2 and testing the results, three further members of this sequence have been found: 2723957777, 1260049494294190236301929754269107568067 and 103945392111236434211250670719387720140245499. I have not included these in the list of members above as they were not arrived at through brute force as the first 4 terms were and there may be other intervening terms.

Links

Table of n, a(n) for n=1..16.

Example

a(3)=9491 because 9491 is a factor of 948894899490.

Crossrefs

Cf. A069860, A088797, A088798.

Sequence in context: A034797 A212814 A101710 * A372101 A181405 A354568

Adjacent sequences: A088796 A088797 A088798 * A088800 A088801 A088802

Keyword

base,nonn

Author

Chuck Seggelin (barkeep(AT)plastereddragon.com), Oct 19 2003

Extensions

More terms from David Wasserman, Aug 25 2005

Status

approved