OFFSET
1,2
COMMENTS
Totally multiplicative sequence with a(p) = p^p for prime p. - Jaroslav Krizek, Oct 17 2009
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + 1/(p^p - 1)) = 1.3850602852044891763... - Amiram Eldar, Dec 08 2020
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..388
FORMULA
Multiplicative with a(p^e) = p^(pe). If n = Product p(k)^e(k) then a(n) = Product p(k)^(p(k)*e(k)). - Jaroslav Krizek, Oct 17 2009
EXAMPLE
a(6) = a(2^1*3^1) = 2^2^1*3^3^1 = 4*27 = 108.
MAPLE
A133482 := proc(n) local ifs, f ; if n = 1 then 1; else ifs := ifactors(n)[2] ; mul( (op(1, f)^op(1, f))^op(2, f), f=ifs) ; fi ; end: seq(A133482(n), n=1..30) ; # R. J. Mathar, Nov 30 2007
MATHEMATICA
f[p_, e_] := (p^(p*e)); a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 30] (* Amiram Eldar, Dec 08 2020 *)
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Masahiko Shin, Nov 29 2007
EXTENSIONS
Corrected and extended by R. J. Mathar, Nov 30 2007
STATUS
approved