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A167343
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Totally multiplicative sequence with a(p) = (p-1)^2 = p^2-2p+1 for prime p.
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1
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1, 1, 4, 1, 16, 4, 36, 1, 16, 16, 100, 4, 144, 36, 64, 1, 256, 16, 324, 16, 144, 100, 484, 4, 256, 144, 64, 36, 784, 64, 900, 1, 400, 256, 576, 16, 1296, 324, 576, 16, 1600, 144, 1764, 100, 256, 484, 2116, 4, 1296, 256
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OFFSET
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1,3
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LINKS
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FORMULA
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Multiplicative with a(p^e) = ((p-1)^2)^e. If n = Product p(k)^e(k) then a(n) = Product ((p(k)-1)^2)^e(k).
Sum_{k=1..n} a(k) ~ c * n^3, where c = (2/Pi^2) / Product_{p prime} (1 + 1/p^2 + 1/p^3 - 1/p^4) = 0.1229567616... . - Amiram Eldar, Dec 15 2022
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MATHEMATICA
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a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 1)^fi[[All, 2]])); Table[a[n]^2, {n, 1, 100}] (* G. C. Greubel, Jun 10 2016 *)
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CROSSREFS
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KEYWORD
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nonn,mult
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AUTHOR
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STATUS
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approved
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