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A112622
If p^b(p,n) is the highest power of the prime p dividing n, then a(n) = product_{p|n} b(p,n)^b(p,n).
3
1, 1, 1, 4, 1, 1, 1, 27, 4, 1, 1, 4, 1, 1, 1, 256, 1, 4, 1, 4, 1, 1, 1, 27, 4, 1, 27, 4, 1, 1, 1, 3125, 1, 1, 1, 16, 1, 1, 1, 27, 1, 1, 1, 4, 4, 1, 1, 256, 4, 4, 1, 4, 1, 27, 1, 27, 1, 1, 1, 4, 1, 1, 4, 46656, 1, 1, 1, 4, 1, 1, 1, 108, 1, 1, 4, 4, 1, 1, 1, 256, 256, 1, 1, 4, 1, 1, 1, 27, 1, 4, 1, 4, 1, 1, 1, 3125, 1, 4, 4, 16, 1, 1, 1, 27, 1
OFFSET
1,4
COMMENTS
a(1) = 1 (empty product).
LINKS
EXAMPLE
45 = 3^2 * 5^1. So a(45) = 2^2 * 1^1 = 4.
72 = 2^3 * 3^2. So a(72) = 3^3 * 2^2 = 108.
MATHEMATICA
f[n_] := Block[{fi = Last@Transpose@FactorInteger@n}, Times @@ (fi^fi)]; Rest@Array[f, 93] (* Robert G. Wilson v *)
PROG
(PARI) a(n)=local(v, r, i); v=factorint(n); r=1; for(i=1, matsize(v)[1], r*=v[i, 2]^v[i, 2]); r (Herrgesell)
CROSSREFS
Sequence in context: A348989 A362297 A354358 * A183104 A183102 A178649
KEYWORD
nonn,mult
AUTHOR
Leroy Quet, Dec 25 2005
EXTENSIONS
More terms from Robert G. Wilson v and Lambert Herrgesell (zero815(AT)googlemail.com), Dec 27 2005
Corrected the starting offset, data section extended to 105 terms - Antti Karttunen, May 28 2017
STATUS
approved