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 A167354 Totally multiplicative sequence with a(p) = (p-2)^2 = p^2-4p+4 for prime p. 1
 1, 0, 1, 0, 9, 0, 25, 0, 1, 0, 81, 0, 121, 0, 9, 0, 225, 0, 289, 0, 25, 0, 441, 0, 81, 0, 1, 0, 729, 0, 841, 0, 81, 0, 225, 0, 1225, 0, 121, 0, 1521, 0, 1681, 0, 9, 0, 2025, 0, 625, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS G. C. Greubel, Table of n, a(n) for n = 1..1000 FORMULA Multiplicative with a(p^e) = ((p-2)^2)^e. If n = Product p(k)^e(k) then a(n) = Product ((p(k)-2)^2)^e(k). a(2k) = 0 for k >= 1. a(n) = A166586(n)^2. Sum_{k=1..n} a(k) ~ c * n^3, where c = 1 / (3 * Product_{p prime} (1 + 4/p^2)) = 0.08140990308... . - Amiram Eldar, Dec 15 2022 MATHEMATICA a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 2)^fi[[All, 2]])); Table[a[n]^2, {n, 1, 100}] (* G. C. Greubel, Jun 11 2016 *) CROSSREFS Cf. A166586. Sequence in context: A007394 A067153 A057405 * A005066 A076262 A167301 Adjacent sequences: A167351 A167352 A167353 * A167355 A167356 A167357 KEYWORD nonn,mult AUTHOR Jaroslav Krizek, Nov 01 2009 STATUS approved

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Last modified September 12 09:33 EDT 2024. Contains 375850 sequences. (Running on oeis4.)