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A105119
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Numbers obtained by rotating right the indices in the prime signature of n.
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6
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 18, 13, 14, 15, 16, 17, 12, 19, 50, 21, 22, 23, 54, 25, 26, 27, 98, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 250, 41, 42, 43, 242, 75, 46, 47, 162, 49, 20, 51, 338, 53, 24, 55, 686, 57, 58, 59, 90, 61, 62, 147, 64, 65, 66, 67, 578, 69, 70
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OFFSET
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1,2
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COMMENTS
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If n = p^a*q^b*r^c, then a(n) = p^c*q^a*r^b.
If n = p^a*q^b*r^c*s^d, then a(n) = p^d*q^a*r^b*s^c.
The sequence is a permutation of the positive integers. The first term which is different from A069799 is a(60).
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LINKS
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EXAMPLE
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a(60) = a(2^2*3*5) = 2*3^2*5 = 90.
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MAPLE
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f:= proc(n) local F, j, m;
F:= ifactors(n)[2];
m:= nops(F);
mul(F[i, 1]^F[i-1, 2], i=2..m)*F[1, 1]^F[m, 2] ;
end proc:
f(1):= 1:
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MATHEMATICA
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Table[Times @@ ((ar = Transpose[FactorInteger[n]])[[1]]^RotateRight[ar[[2]]]), {n, 70}] (* Ivan Neretin, Jul 26 2015 *)
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PROG
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(PARI) a(n)=local(m, s); m=factor(n); s=matsize(m)[1]; prod(i=2, s, m[i, 1]^m[i-1, 2])*m[1, 1]^m[s, 2] /* Ralf Stephan, Apr 05 2009 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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