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 A116172 #10 Jul 20 2021 23:47:06 %S A116172 2,74,59264,510782,906902,81790664,92776472,10876856041862, %T A116172 11796926254874,18332259798794,18388650720624,32624670587648, %U A116172 32699883214248,43103618706398,44916698243804,66132258426302 %N A116172 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 5. %C A116172 Also numbers k such that k concatenated with k+6 gives the product of two numbers which differ by 3. %C A116172 Also numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 1. %C A116172 If k+2 and k-4 have the same number of digits, then k is also in A116132 because k//k+2 = 10^d*k + k + 2 = m*(m+5) then implies k//k-4 = 10^d*k + k - 4 = m*(m+5) - 6 = (m-1)*(m+6). - _R. J. Mathar_, Aug 10 2008 %e A116172 92776472//92776474 = 96320542 * 96320547, where // denotes concatenation. %e A116172 92776472//92776480 = 96320544 * 96320545. %e A116172 92776472//92776478 = 96320543 * 96320546. %Y A116172 Cf. A116158, A116171, A116173, A116179, A116303. %Y A116172 Cf. A116185, A115430, A116205, A116343, A116200, A116330. %K A116172 nonn,base %O A116172 1,1 %A A116172 _Giovanni Resta_, Feb 06 2006 %E A116172 Edited by _N. J. A. Sloane_, Apr 15 2007