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A167323
Totally multiplicative sequence with a(p) = 4*(p+3) for prime p.
1
1, 20, 24, 400, 32, 480, 40, 8000, 576, 640, 56, 9600, 64, 800, 768, 160000, 80, 11520, 88, 12800, 960, 1120, 104, 192000, 1024, 1280, 13824, 16000, 128, 15360, 136, 3200000, 1344, 1600, 1280, 230400, 160, 1760, 1536, 256000, 176, 19200, 184, 22400
OFFSET
1,2
LINKS
FORMULA
Multiplicative with a(p^e) = (4*(p+3))^e. If n = Product p(k)^e(k) then a(n) = Product (4*(p(k)+3))^e(k).
a(n) = A165825(n) * A166591(n) = 4^bigomega(n) * A166591(n) = 4^A001222(n) * A166591(n).
MATHEMATICA
a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 3)^fi[[All, 2]])); Table[a[n]*4^PrimeOmega[n], {n, 1, 100}] (* G. C. Greubel, Jun 09 2016 *)
f[p_, e_] := (4*(p+3))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 22 2023 *)
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Jaroslav Krizek, Nov 01 2009
STATUS
approved