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A167341 Totally multiplicative sequence with a(p) = p*(p-3) = p^2-3p for prime p. 1
1, -2, 0, 4, 10, 0, 28, -8, 0, -20, 88, 0, 130, -56, 0, 16, 238, 0, 304, 40, 0, -176, 460, 0, 100, -260, 0, 112, 754, 0, 868, -32, 0, -476, 280, 0, 1258, -608, 0, -80, 1558, 0, 1720, 352, 0, -920, 2068, 0, 784, -200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

Multiplicative with a(p^e) = (p*(p-3))^e. If n = Product p(k)^e(k) then a(n) = Product (p(k)*(p(k)-3))^e(k).

a(3k) = 0 for k >= 1.

a(n) = n * A166589(n).

MATHEMATICA

a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 3)^fi[[All, 2]])); Table[a[n]*n, {n, 1, 100}] (* G. C. Greubel, Jun 10 2016 *)

CROSSREFS

Sequence in context: A111938 A224822 A246928 * A214199 A320491 A295907

Adjacent sequences:  A167338 A167339 A167340 * A167342 A167343 A167344

KEYWORD

sign,mult

AUTHOR

Jaroslav Krizek, Nov 01 2009

STATUS

approved

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Last modified September 17 11:03 EDT 2019. Contains 327129 sequences. (Running on oeis4.)