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Numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 5.
11

%I #8 Jul 19 2021 22:37:03

%S 11,45,18281,32769,56891,180689,330539,959481,1850201,3247409,4940219,

%T 2425563239,2575561739,6003563495,7245212645,7770160145,4983798265289,

%U 5049762270381,5534298528989,5603798594169,21894082450101

%N Numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 5.

%C Also numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 3. For proof that this is the same sequence compare A116133.

%C Also numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 9.

%e 7770160145//7770160136 = 8814851183 * 8814851192, where // denotes concatenation.

%Y Cf. A116205, A116187, A116349.

%Y Cf. A116179, A115430, A116194, A116200, A116324.

%Y Cf. A116099, A116109, A116231.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 06 2006

%E Edited by _N. J. A. Sloane_, Apr 12 2007