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A345939
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a(n) = (n-1) / gcd(n-1, uphi(n)), where uphi is unitary totient (or unitary phi) function, A047994.
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4
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0, 1, 1, 1, 1, 5, 1, 1, 1, 9, 1, 11, 1, 13, 7, 1, 1, 17, 1, 19, 5, 21, 1, 23, 1, 25, 1, 3, 1, 29, 1, 1, 8, 33, 17, 35, 1, 37, 19, 39, 1, 41, 1, 43, 11, 45, 1, 47, 1, 49, 25, 17, 1, 53, 27, 55, 14, 57, 1, 59, 1, 61, 31, 1, 4, 13, 1, 67, 17, 23, 1, 71, 1, 73, 37, 25, 19, 77, 1, 79, 1, 81, 1, 83, 21, 85, 43, 87, 1, 89, 5, 91
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OFFSET
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1,6
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LINKS
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FORMULA
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a(2n-1) = A345949(2n-1), for n > 1.
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MATHEMATICA
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uphi[1]=1; uphi[n_]:=Times@@(#[[1]]^#[[2]]-1&/@FactorInteger[n]);
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PROG
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(PARI)
A047994(n) = { my(f=factor(n)~); prod(i=1, #f, (f[1, i]^f[2, i])-1); };
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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