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 A193380 #8 Oct 26 2012 10:21:35 %S A193380 1,16,218,24277,282624223,35336530286,4038946460332,454417916411629, %T A193380 50493713793377093,5554535251494847465,605967851146914507796, %U A193380 65648063122810597558064,7069922221437372952524460,714212835424956578936007364364293 %N A193380 A192392(n)/n = largest m such that m*n is a concatenation of the numbers n(n-1)/2+1,...,n(n+1)/2. %F A193380 a(n) = A192392(n)/n. %o A193380 (PARI) a(n) = A192392(n)/n /* see there */ %Y A193380 Cf. A076068 - A076073, A080479, A080480, A192392. %K A193380 nonn,base %O A193380 1,2 %A A193380 _M. F. Hasler_, Jul 24 2011