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A167328
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Totally multiplicative sequence with a(p) = 9*(p+3) for prime p.
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1
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1, 45, 54, 2025, 72, 2430, 90, 91125, 2916, 3240, 126, 109350, 144, 4050, 3888, 4100625, 180, 131220, 198, 145800, 4860, 5670, 234, 4920750, 5184, 6480, 157464, 182250, 288, 174960, 306, 184528125, 6804, 8100, 6480, 5904900, 360, 8910, 7776, 6561000, 396, 218700
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OFFSET
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1,2
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LINKS
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FORMULA
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Multiplicative with a(p^e) = (9*(p+3))^e. If n = Product p(k)^e(k) then a(n) = Product (9*(p(k)+3))^e(k).
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MATHEMATICA
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a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 3)^fi[[All, 2]])); Table[a[n]*9^PrimeOmega[n], {n, 1, 100}] (* G. C. Greubel, Jun 09 2016 *)
f[p_, e_] := (9*(p+3))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 21 2023 *)
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CROSSREFS
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KEYWORD
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nonn,easy,mult
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AUTHOR
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STATUS
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approved
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