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A167301 Totally multiplicative sequence with a(p) = 9*(p-2) for prime p. 1
1, 0, 9, 0, 27, 0, 45, 0, 81, 0, 81, 0, 99, 0, 243, 0, 135, 0, 153, 0, 405, 0, 189, 0, 729, 0, 729, 0, 243, 0, 261, 0, 729, 0, 1215, 0, 315, 0, 891, 0, 351, 0, 369, 0, 2187, 0, 405, 0, 2025, 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) = (9*(p-2))^e. If n = Product p(k)^e(k) then a(n) = Product (9*(p(k)-2))^e(k). a(2k) = 0 for k >= 1. a(n) = A165830(n) * A166586(n) = 9^bigomega(n) * A166586(n) = 9^A001222(n) * A166586(n).

MATHEMATICA

a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] - 2)^fi[[All, 2]])); Table[a[n]*9^PrimeOmega[n], {n, 1, 100}] (* G. C. Greubel, Jun 07 2016 *)

CROSSREFS

Sequence in context: A167354 A005066 A076262 * A177741 A182213 A340954

Adjacent sequences:  A167298 A167299 A167300 * A167302 A167303 A167304

KEYWORD

nonn,mult

AUTHOR

Jaroslav Krizek, Nov 01 2009

STATUS

approved

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Last modified May 18 13:16 EDT 2021. Contains 343995 sequences. (Running on oeis4.)