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A167351 Totally multiplicative sequence with a(p) = (p+1)*(p+2) = p^2+3p+2 for prime p. 1
1, 12, 20, 144, 42, 240, 72, 1728, 400, 504, 156, 2880, 210, 864, 840, 20736, 342, 4800, 420, 6048, 1440, 1872, 600, 34560, 1764, 2520, 8000, 10368, 930, 10080, 1056, 248832, 3120, 4104, 3024, 57600, 1482, 5040, 4200, 72576, 1806, 17280, 1980, 22464 (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+1)*(p+2))^e. If n = Product p(k)^e(k) then a(n) = Product ((p(k)+1)*(p(k)+2))^e(k). a(n) = A003959(n) * A166590(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: A025104 A163323 A060159 * A231400 A231467 A078600

Adjacent sequences:  A167348 A167349 A167350 * A167352 A167353 A167354

KEYWORD

nonn,mult

AUTHOR

Jaroslav Krizek, Nov 01 2009

STATUS

approved

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Last modified June 4 05:58 EDT 2020. Contains 334816 sequences. (Running on oeis4.)