A116180 Numbers k such that k concatenated with k+3 gives the product of two numbers which differ by 7.

7137, 7767, 47783068991048776635, 48797525371338932241, 55658688122404752991, 56753136503494828605, 85555875266989354735, 86911515887391841491, 95992713077544748491, 97428345698747155255

Offset: 1

Author

Giovanni Resta, Feb 06 2006

Keywords

• nonn
• base

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.

Examples

			7767//7770 = 8810 * 8817, where // denotes concatenation.
7767//7762 = 8809 * 8818.
7767//7776 = 8811 * 8816.
		

Crossrefs

Cf. A116167, A116179, A116181, A116133, A116311.

Cf. A116114, A116126, A116133, A116258.

Cf. A116207, A116187, A116174, A116351.

Extensions

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