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%I #10 Jul 20 2021 23:47:12
%S 6752089,6448802889351008245,
%T 18894512461523256139943105859903480218905,
%U 31958875438439894736354375209245786214798
%N Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 6.
%C Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 4.
%C If k+2 and k-5 have the same number of digits, the k is also in A116126, because k//k+2 = 10^d*k + k + 2 = m*(m+6) then implies a representation k//k-5 = 10^d*k + k - 5 = m*(m+6)-7 = (m-1)*(m+7). - _R. J. Mathar_, Aug 10 2008
%e 6752089//6752091 = 8217107 * 8217113, where // denotes concatenation.
%e 6752089//6752096 = 8217108 * 8217112.
%Y Cf. A116159, A116172, A116174, A116187, A116304.
%Y Cf. A115430, A116205, A116207, A116187, A116337.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Feb 06 2006
%E Edited by _N. J. A. Sloane_, Apr 12 2007
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