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A116180
Numbers k such that k concatenated with k+3 gives the product of two numbers which differ by 7.
12
7137, 7767, 47783068991048776635, 48797525371338932241, 55658688122404752991, 56753136503494828605, 85555875266989354735, 86911515887391841491, 95992713077544748491, 97428345698747155255
OFFSET
1,1
COMMENTS
Also numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 9.
Also numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 5.
EXAMPLE
7767//7770 = 8810 * 8817, where // denotes concatenation.
7767//7762 = 8809 * 8818.
7767//7776 = 8811 * 8816.
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Feb 06 2006
EXTENSIONS
Edited by N. J. A. Sloane, Apr 12 2007
STATUS
approved