

A116173


Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 6.


9




OFFSET

1,1


COMMENTS

Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 4.
If k+2 and k5 have the same number of digits, the k is also in A116126, because k//k+2 = 10^d*k + k + 2 = m*(m+6) then implies a representation k//k5 = 10^d*k + k  5 = m*(m+6)7 = (m1)*(m+7).  R. J. Mathar, Aug 10 2008


LINKS

Table of n, a(n) for n=1..4.


EXAMPLE

6752089//6752091 = 8217107 * 8217113, where // denotes concatenation.
6752089//6752096 = 8217108 * 8217112.


CROSSREFS

Cf. A116159, A116172, A116174, A116187, A116304.
Cf. A115430, A116205, A116207, A116187, A116337.
Sequence in context: A309385 A022237 A273753 * A345608 A346282 A088238
Adjacent sequences: A116170 A116171 A116172 * A116174 A116175 A116176


KEYWORD

nonn,base


AUTHOR

Giovanni Resta, Feb 06 2006


EXTENSIONS

Edited by N. J. A. Sloane, Apr 12 2007


STATUS

approved



