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A167305
Totally multiplicative sequence with a(p) = 4*(p+2) for prime p.
1
1, 16, 20, 256, 28, 320, 36, 4096, 400, 448, 52, 5120, 60, 576, 560, 65536, 76, 6400, 84, 7168, 720, 832, 100, 81920, 784, 960, 8000, 9216, 124, 8960, 132, 1048576, 1040, 1216, 1008, 102400, 156, 1344, 1200, 114688, 172, 11520, 180, 13312, 11200, 1600
OFFSET
1,2
LINKS
FORMULA
Multiplicative with a(p^e) = (4*(p+2))^e. If n = Product p(k)^e(k) then a(n) = Product (4*(p(k)+2))^e(k).
a(n) = A165825(n) * A166590(n) = 4^bigomega(n) * A166590(n) = 4^A001222(n) * A166590(n).
MATHEMATICA
a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 2)^fi[[All, 2]])); Table[a[n]*4^PrimeOmega[n], {n, 1, 100}] (* G. C. Greubel, Jun 07 2016 *)
f[p_, e_] := (4*(p+2))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 21 2023 *)
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Jaroslav Krizek, Nov 01 2009
STATUS
approved