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 A281592 #18 Apr 15 2017 09:58:53
%S A281592 138,777,4642,10258,10263,12207,13282,16167,19762,30783,37407,38482,
%T A281592 46978,48927,56127,60145,63543,73767,81687,89823,95367,95627,103863,
%U A281592 110905,115527,128545,202705,208879,223643,284119,324947,325793,360151,395003,477538,541163,558322,585538,672199,673693,780082,914551,1016643
%N A281592 Products of three distinct primes p1, p2 and p3 (sphenic numbers) with p1<p2 and p3 is the concatenation of p1 with p2.
%e A281592 10258 is in the sequence because 10258 = 2*23*223 and 223 is the concatenation of 2 with 23.
%t A281592 c[x_, y_] := x 10^IntegerLength[y] + y; upto[mx_] := Sort@ Reap[Block[{p=2, q=3, v=1}, While[v <= mx, While[p < q && (v = p q (r = c[p, q])) <= mx, If[PrimeQ@r, Sow@v]; p = NextPrime[p]]; p=2; q = NextPrime[q]; v = p q c[p, q]]]][[2, 1]]; upto[10^6] (* _Giovanni Resta_, Apr 14 2017 *)
%o A281592 (PARI) isok(n) = f = factor(n); ((#f~ == 3) && (vecmax(f[,2]) == 1) && (f[3,1] == fromdigits(concat(digits(f[1,1]), digits(f[2,1]))))); \\ _Michel Marcus_, Apr 14 2017
%Y A281592 Cf. A007304, A133980 (the p3 primes).
%K A281592 nonn,base
%O A281592 1,1
%A A281592 _Peter Weiss_, Apr 14 2017