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 A238499 #9 Jun 09 2025 13:29:52
%S A238499 3137,3797,13997,19937,19997,23911,23929,29173,29311,31193,37337,
%T A238499 37397,43397,59929,73331,78737,79337,103997,109397,127997,139967,
%U A238499 173347,173359,193337,193373,193877,199337,199373,199967,229373,233113,233329,233353,233617
%N A238499 Primes which are the concatenation of two primes in exactly three ways.
%H A238499 Giovanni Resta, <a href="/A238499/b238499.txt">Table of n, a(n) for n = 1..10000</a>
%e A238499 13997 is in the sequence because (13, 997), (139, 97), (1399, 7) are all primes, so there are three ways.
%t A238499 spl[n_] := Block[{d = IntegerDigits@n, c = 0, z}, z = Length@d; Do[If[PrimeQ@ FromDigits@ Take[d, k] && d[[k + 1]] > 0 && PrimeQ@ FromDigits@ Take[d, k - z], c++], {k, z - 1}]; c]; Select[ Prime@ Range@ 20000, spl[#] == 3 &] (* _Giovanni Resta_, Mar 03 2014 *)
%Y A238499 Cf. A105184, A238056, A238057, A238500.
%K A238499 nonn,base
%O A238499 1,1
%A A238499 _Colin Barker_, Feb 27 2014
%E A238499 Example clarified by _Harvey P. Dale_, Jun 09 2025