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 A152397 #32 Aug 12 2015 02:37:22 %S A152397 4,10,73,100,8338 %N A152397 Similar to A152396, but here the requirement is for finding any n primes, not necessarily from the shortest concatenations. %C A152397 Tentatively, as of Dec 2012, the likely value of a(6) is 20968. A noteworthy fact, perhaps, is that were this sequence to limit itself to non-titanic primes (ones under 10^999), then it would look the same to the point shown and have the stated tentative value for a(6) as its a(5), despite there being a number of smaller values eventually reaching a 5th prime. - _James G. Merickel_, Dec 06 2012 %C A152397 a(5)=8338 has not been determined with complete certainty, but is likely correct (See A232657). a(6)=20968 has fairly convincing support, but even finding a good upper bound for a(7) is hard. - _James G. Merickel_, Jun 14 2014 %e A152397 21, 32, and 321 are all composite, and 43 is prime. So a(1)=4. Then the first stem resulting in 2 primes is 10, with 109 and 10987 both prime. So a(2)=10. 73 produces 4 primes in this way if improper concatenation (including 73 itself) is included, but it is not. Since stem values from 11 through 72 never produce more than 2 primes properly, a(3)=73. %Y A152397 Cf. A152396, A232657. %K A152397 nonn,base,more %O A152397 1,1 %A A152397 _James G. Merickel_, Oct 20 2009 %E A152397 a(5) added by _James G. Merickel_, Feb 06 2014