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A167345 Totally multiplicative sequence with a(p) = (p-1)*(p-2) = p^2-3p+2 for prime p. 1
1, 0, 2, 0, 12, 0, 30, 0, 4, 0, 90, 0, 132, 0, 24, 0, 240, 0, 306, 0, 60, 0, 462, 0, 144, 0, 8, 0, 756, 0, 870, 0, 180, 0, 360, 0, 1260, 0, 264, 0, 1560, 0, 1722, 0, 48, 0, 2070, 0, 900, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

FORMULA

Multiplicative with a(p^e) = ((p-1)*(p-2))^e. If n = Product p(k)^e(k) then a(n) = Product ((p(k)-1)*(p(k)-2))^e(k). a(2k) = 0 for k >= 1, a(n) = A003958(n) * A166586(n).

MATHEMATICA

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

CROSSREFS

Sequence in context: A053814 A293260 A095238 * A292496 A285480 A156431

Adjacent sequences:  A167342 A167343 A167344 * A167346 A167347 A167348

KEYWORD

nonn,mult

AUTHOR

Jaroslav Krizek, Nov 01 2009

STATUS

approved

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Last modified March 5 16:55 EST 2021. Contains 341827 sequences. (Running on oeis4.)