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 A146892 For definition see comments lines. 3
 1, 6, 6, 72, 72, 72, 6, 72, 72, 5184, 6, 5184, 72, 5184, 31104, 5184, 5184, 5184, 2592, 5184, 432, 373248, 36, 373248, 31104, 26873856, 26873856, 26873856, 373248, 31104, 36, 31104, 2239488, 2239488, 1934917632, 26873856, 31104, 2239488 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Let USigma denote the unitary sigma function, A034448. 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. 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. [How to compute c(m)] Case of Base Primes = {2}{3} c(0)=2^m, b(0)=2^m c(n)=c(n-1)/PF_2[USigma[b(n-1)]]*PF_3[USigma[b(n-1)]] b(n)=USigma[b(n-1)]/ PF_2,3[USigma[b(n-1)]] IF b(k)=1 THEN END a(m)=c(k) Sequence gives a(m) Factorization of term becomes 2^r*3^s. LINKS MAPLE A146892 := proc(n) local b, a, k ; b := [2^n] ; while op(-1, b) <> 1 do b := [op(b), A065330(A034448(op(-1, b))) ] ; od: a := 2^n ; for k from 2 to nops(b) do a := a/ A006519(A034448(op(k-1, b))) *A038500(A034448(op(k-1, b))) ; od: a ; end: # R. J. Mathar, Jun 24 2009 CROSSREFS Cf. A146891. Sequence in context: A269888 A269767 A065239 * A347916 A320824 A085804 Adjacent sequences: A146889 A146890 A146891 * A146893 A146894 A146895 KEYWORD nonn,uned AUTHOR Yasutoshi Kohmoto, Apr 17 2009 EXTENSIONS More terms from R. J. Mathar, Jun 24 2009 STATUS approved

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Last modified December 6 14:37 EST 2022. Contains 358643 sequences. (Running on oeis4.)