OFFSET
1,1
COMMENTS
Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 2.
Also numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 4.
Also numbers k such that k concatenated with k-1 gives the product of two numbers which differ by 6.
Also numbers k such that k concatenated with k-8 gives the product of two numbers which differ by 8.
EXAMPLE
6001//6009 = 7747^2, where // denotes concatenation.
96040393//96040400 = 98000200 * 98000202.
96040393//96040397 = 98000199 * 98000203.
96040393//96040392 = 98000198 * 98000204.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Giovanni Resta, Jan 24 2006
EXTENSIONS
Edited by N. J. A. Sloane, Apr 15 2007
STATUS
approved