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 A177962 #10 Feb 02 2015 11:04:18 %S A177962 1,2,1,1,2,3,2,2,1,3,3,2,2,4,1,2,1,3,6,1,2,2,2,6,2,2,4,6,3,3,2,5,1,3, %T A177962 2,3,4,2,4,2,2,12,2,3,1,2,6,3,2,6,10,2,3,3,2,6,5,1,2,12,2,2,2,4,12,2, %U A177962 3,2,2,2,6,3,3,6,6,4,6,2,10,6,2,5,6,2,3,3,2,2,20,1,2,2,3,1,12,1,2,6,12,2,2 %N A177962 Number of distinct transpositions of prime factors of n-th composite number. %F A177962 a(n) = A008480(A002808(n)). - _R. J. Mathar_, May 28 2010 %e A177962 a(1)=1 because 1st composite = 4 and (2*2)=1. %e A177962 a(2)=2 because 2nd composite = 6 and (2*3 or 3*2) = 2. %p A177962 A177962 := proc(n) local c; c := A002808(n) ; a := (numtheory[bigomega](c))! ; for p in ifactors(c)[2] do a := a/ op(2,p)! ; end do: a ; end proc: %p A177962 seq(A177962(n),n=1..120) ; # _R. J. Mathar_, May 28 2010 %Y A177962 Cf. A002808, A177687. %K A177962 nonn %O A177962 1,2 %A A177962 _Juri-Stepan Gerasimov_, May 16 2010 %E A177962 Entries checked by _R. J. Mathar_, May 28 2010