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A167320 Totally multiplicative sequence with a(p) = 10*(p-3) for prime p. 1
1, -10, 0, 100, 20, 0, 40, -1000, 0, -200, 80, 0, 100, -400, 0, 10000, 140, 0, 160, 2000, 0, -800, 200, 0, 400, -1000, 0, 4000, 260, 0, 280, -100000, 0, -1400, 800, 0, 340, -1600, 0, -20000, 380, 0, 400, 8000, 0, -2000, 440, 0, 1600, -4000 (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) = (10*(p-3))^e. If n = Product p(k)^e(k) then a(n) = Product (10*(p(k)-3))^e(k). a(3k) = 0 for k >= 1. a(n) = A165831(n) * A166589(n) = 10^bigomega(n) * A166589(n) = 10^A001222(n) * A166589(n).

MATHEMATICA

a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 3)^fi[[All, 2]])); Table[a[n]*10^PrimeOmega[n], {n, 1, 100}] (* G. C. Greubel, Jun 09 2016 *)

CROSSREFS

Sequence in context: A286774 A285772 A171008 * A092916 A285780 A285536

Adjacent sequences:  A167317 A167318 A167319 * A167321 A167322 A167323

KEYWORD

sign,mult

AUTHOR

Jaroslav Krizek, Nov 01 2009

STATUS

approved

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Last modified June 20 19:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)