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 A034817 #5 Oct 06 2019 18:18:06 %S A034817 63,333,621,3339,4557,8127,13977,16827,18177,21921,27393,34989,40023, %T A034817 40047,46917,59727,61203,79467,94767,95079,100821,102771,104859, %U A034817 106527,113883,114123,143433,147123,156201,158409,160149,196737,209277,209961 %N A034817 Concatenations C1 and C2 and C3 are all prime (see the comment lines). %C A034817 C1 = 'prevprime(n) followed by n' %C A034817 C2 = 'n followed by nextprime(n)' %C A034817 C3 = 'prevprime(n) followed by n followed by nextprime(n)' %e A034817 n=95079 -> previous prime is 95071, next prime is 95083, thus '9501795079' and '9507995083' and '950719507995083' are all three primes. %Y A034817 Cf. A034808-A034821. %K A034817 nonn,base %O A034817 0,1 %A A034817 _Patrick De Geest_, Oct 15 1998