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%I #6 Jul 20 2021 23:45:32
%S 13,41,653,2287,2723,5491,23240971,26823191,60249661,1841968537,
%T 2009317771,3044234903,3258336353,8166731261,9481619237,
%U 1281071245505271100098621541,1551605670846640136726379653
%N Numbers k such that k concatenated with k-1 gives the product of two numbers which differ by 9.
%Y Cf. A116147, A116152, A116162, A116284.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Feb 06 2006