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%I #7 Aug 06 2017 21:35:25
%S 1,6,6,72,72,72,6,72,72,5184,6,5184,72,5184,31104,5184,5184,5184,2592,
%T 5184,432,373248,36,373248,31104,26873856,26873856,26873856,373248,
%U 31104,36,31104,2239488,2239488,1934917632,26873856,31104,2239488
%N For definition see comments lines.
%C Let USigma denote the unitary sigma function, A034448.
%C As in A146891, let PF_p(n) denote the largest power of the prime p dividing n. PF_2 is A006519, and PF_3 is A038500. Furthermore define PF_1(n)=1.
%C Extension to multi-prime-indices is done by multiplying the corresponding functions: PF_{p,q,..}(n) = PF_p(n)*PF_q(n)*... An example of this is PF_{2,3} = A065331.
%C [How to compute c(m)]
%C Case of Base Primes = {2}{3}
%C c(0)=2^m, b(0)=2^m
%C c(n)=c(n-1)/PF_2[USigma[b(n-1)]]*PF_3[USigma[b(n-1)]]
%C b(n)=USigma[b(n-1)]/ PF_2,3[USigma[b(n-1)]]
%C IF b(k)=1 THEN END
%C a(m)=c(k)
%C Sequence gives a(m)
%C Factorization of term becomes 2^r*3^s.
%p A146892 := proc(n) local b,a,k ;
%p b := [2^n] ;
%p while op(-1,b) <> 1 do
%p b := [op(b), A065330(A034448(op(-1,b))) ] ;
%p od:
%p a := 2^n ;
%p for k from 2 to nops(b) do
%p a := a/ A006519(A034448(op(k-1,b))) *A038500(A034448(op(k-1,b))) ;
%p od:
%p a ;
%p end: # _R. J. Mathar_, Jun 24 2009
%Y Cf. A146891.
%K nonn,uned
%O 0,2
%A _Yasutoshi Kohmoto_, Apr 17 2009
%E More terms from _R. J. Mathar_, Jun 24 2009
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