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 A079617 #6 Mar 31 2012 13:21:55 %S A079617 1,1,2,1,3,1,4,2,3,1,5,1,3,3,6,1,5,1,5,3,3,1,7,2,3,4,5,1,8,1,9,3,3,3, %T A079617 10,1,3,3,7,1,8,1,5,5,3,1,11,2,5,3,5,1,7,3,7,3,3,1,12,1,3,5,13,3,8,1, %U A079617 5,3,8,1,14,1,3,5,5,3,8,1,11,6,3,1,12,3,3,3,7,1,12,3,5,3,3,3,15,1,5,5,10,1,8 %N A079617 Occurrences of prime factorization templates, unordered. %C A079617 1=p, 2=p^2, 3=p.q, 4=p^3, 5=p^2.q, 6=p^4 7=p^3.q, 8=p.q.r, 9=p^5, 10=p^2.q^2, 11=p^4.q %F A079617 a(n) = A101296(n)-1. - _David Wasserman_, Dec 27 2004 %e A079617 Primes are given 1. The next prime factorization pattern is 4=p^2, so a(4)=2 and similarly a(6)=3. a(12)=a(18), etc... %o A079617 (PARI) primetemplate2(n)=local(f,fl,fs,res,eres); f=factor(n); fl=length(f[,1]); fs=f[,2]; fs=vecsort(fs); res=""; for (i=1,fl,res=concat(res,fs[i])); eres=eval(res); if (v[eres]==0,v[eres]=vc; vc++); eres vc=1; v=vector(10000); for (j=2,50,print1(v[primetemplate2(j)]",")) %Y A079617 Cf. A037916, A079616. %K A079617 nonn %O A079617 2,3 %A A079617 _Jon Perry_, Jan 29 2003 %E A079617 More terms from _David Wasserman_, Dec 27 2004