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Numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 9.
4

%I #6 Jul 18 2021 21:40:42

%S 1953,3115,6153,1016574047215119910181525023,

%T 2440558249789368730986767575,2560156942576450203707692923,

%U 4639822375038697733267413875,4868700733912235016077891029

%N Numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 9.

%e 6153//6160 = 7840 * 7849, where // denotes concatenation.

%Y Cf. A116203, A116210, A116216, A116342.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 06 2006