This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A116173 #10 Jul 20 2021 23:47:12 %S A116173 6752089,6448802889351008245, %T A116173 18894512461523256139943105859903480218905, %U A116173 31958875438439894736354375209245786214798 %N A116173 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 6. %C A116173 Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 4. %C A116173 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 A116173 6752089//6752091 = 8217107 * 8217113, where // denotes concatenation. %e A116173 6752089//6752096 = 8217108 * 8217112. %Y A116173 Cf. A116159, A116172, A116174, A116187, A116304. %Y A116173 Cf. A115430, A116205, A116207, A116187, A116337. %K A116173 nonn,base %O A116173 1,1 %A A116173 _Giovanni Resta_, Feb 06 2006 %E A116173 Edited by _N. J. A. Sloane_, Apr 12 2007