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 A034593 #5 Oct 06 2019 18:27:44 %S A034593 467,941,8834,9548,13012,22302,23592,26208,47538,58578,78910,86447, %T A034593 86925,116230,118040,123716,128055,213493,234146,238326,273057,285315, %U A034593 286422,389336,399261,457810,468764,481476,502590,525402,541102,570205 %N A034593 Cycle of 3 steps possible for 'concatenate a(n) and nextprime(a(n)) is a prime'. %e A034593 a(n)=78910 -> nextprime(a(n)) is 78919 so '7891078919' is prime (=step 1); a(n2)=7891078919 -> nextprime(a(n2)) is 7891078931 so '78910789197891078931' is prime (=step 2); a(n3)=78910789197891078931 -> nextprime(a(n3)) is 78910789197891078949 so '7891078919789107893178910789197891078949' is prime (=step 3). %Y A034593 See also A034591-A034596, A030459. %K A034593 nonn,base %O A034593 0,1 %A A034593 _Patrick De Geest_, Oct 15 1998