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Numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 6.
9

%I #8 Jul 20 2021 23:42:53

%S 7,97,205,300,477,732,997,1920,3157,9997,52896,99997,120085,427020,

%T 999997,8264460,9999997,88581312,99999997,112000885,112917765,

%U 143075580,152863360,193537077,233788192,266755221,313680096

%N Numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 6.

%C Also numbers k such that k concatenated with itself gives the product of two numbers which differ by 4.

%e 6786111717//6786111712 = 8237785936 * 8237785942, where // denotes concatenation.

%Y Cf. A115426, A116124, A116126, A116131, A116256.

%Y Cf. A116130, A116158, A115428, A116288.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 06 2006

%E Edited by _N. J. A. Sloane_, Apr 15 2007