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 A093549 #12 May 20 2014 11:04:52
%S A093549 3,21,645,37961,1042405,323567035,30989984675,10042712381261
%N A093549 a(n) is the smallest number m such that each of the numbers m-1, m and m+1 has n distinct prime divisors.
%C A093549 a(n) <= A093550(n) since here the factors do not occur necessarily to the first power, e.g. a(2)-1 = 20 = 2^2*5, therefore A093550(2) > a(2). - _M. F. Hasler_, May 20 2014
%F A093549 a[n_] := (For[m=2, !(Length[FactorInteger[m-1]]==n && Length[FactorInteger[m]]==n&&Length[FactorInteger[m+1]]==n), m++ ];m)
%e A093549 a(3)=645 because 644=2^2*7*23; 645=3*5*43; 646=2*17*19 and 645 is the smallest number m such that each of the numbers m-1, m and m+1 has 3 distinct prime divisors.
%t A093549 a[n_] := (For[m=2, !(Length[FactorInteger[m-1]]==n && Length[FactorInteger[m]]==n&&Length[FactorInteger[m+1]]==n), m++ ];m);Do[Print[a[n]], {n, 7}]
%o A093549 (PARI) a(n,m=2)=until(,for(k=-1,1,omega(m-k)!=n&&(m+=2-k)&&next(2));return(m)) \\ _M. F. Hasler_, May 20 2014
%Y A093549 Cf. A093550, A052215, A093548.
%K A093549 more,nonn
%O A093549 1,1
%A A093549 _Farideh Firoozbakht_, Apr 07 2004
%E A093549 a(7) from _Donovan Johnson_, Apr 07 2008
%E A093549 a(8) from _Donovan Johnson_, Jan 15 2009