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 A136357 #10 Jul 28 2013 11:52:07
%S A136357 4,6,9,15,30,105,210,2310,3465,15015,120120,765765,4084080,33948915,
%T A136357 106696590,334639305,892371480,3234846615,71166625530,100280245065,
%U A136357 200560490130,3710369067405,29682952539240,1369126185872445
%N A136357 Increasing sequence obtained by union of two sequences A136354 and {b(n)}, where b(n) is the smallest composite number m such that m+1 is prime and the set of distinct prime factors of m consists of the first n primes.
%C A136357 This sequence is different from A070826 and A118750.
%e A136357 a(4)=15 because k=2 with prime factors 3 and 5 and 15 is followed by 17, prime;
%e A136357 a(5)=30 because k=3 with prime factors 2, 3, 5 and 30 is followed by 31, prime.
%t A136357 a[n_]:=(c=Product[Prime[k],{k,n}]; For[m=1,!(!PrimeQ[c*m]&&PrimeQ[c*m+1]&& Length[FactorInteger[c*m]]==n),m++ ]; c*m);
%t A136357 b[n_]:=(c=Product[Prime[k],{k,2, n+1}]; For[m=1,!(!PrimeQ[c(2*m-1)]&&PrimeQ[c(2*m-1)+2]&&Length[FactorInteger [c(2*m-1)]]==n),m++ ]; c(2*m-1));
%t A136357 Take[Union[Table[a[k],{k,24}],Table[b[k],{k, 24}]],24] (* _Farideh Firoozbakht_, Aug 13 2009 *)
%Y A136357 Cf. A136349-A136356, A136358, A070826, A118750.
%K A136357 easy,nonn
%O A136357 1,1
%A A136357 _Enoch Haga_, Dec 25 2007
%E A136357 Edited, corrected and extended by _Farideh Firoozbakht_, Aug 13 2009