OFFSET
1,2
COMMENTS
Product of n-th row of triangle A210208. - Reinhard Zumkeller, Mar 18 2012
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
Multiplicative with a(p^k) = p^(k*(k+1)/2).
The Dirichlet g.f. of a(n) / abs(A153038(n)) is Product_{k >= 0} zeta(s+k). - Álvar Ibeas, Nov 10 2014
EXAMPLE
For n = 12, set of such divisors is {1, 2, 3, 4}; a(12) = 1*2*3*4 = 24.
MAPLE
A183091 := proc(n) local a, d; a := 1 ; for d in numtheory[divisors](n) minus {1} do if nops( numtheory[factorset](d)) = 1 then a := a*d; end if; end do: a ; end proc: # R. J. Mathar, Apr 14 2011
MATHEMATICA
Table[Product[d, {d, Select[Divisors[n], Length[FactorInteger[#]] == 1 &]}], {n, 1, 54}] (* Geoffrey Critzer, Mar 18 2015 *)
f[p_, e_] := p^(e*(e+1)/2); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Aug 31 2023 *)
PROG
(Haskell)
a183091 = product . a210208_row -- Reinhard Zumkeller, Mar 18 2012
(PARI) a(n)=my(f=factor(n)); prod(i=1, #f~, f[i, 1]^binomial(f[i, 2]+1, 2)) \\ Charles R Greathouse IV, Nov 11 2014
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Jaroslav Krizek, Dec 25 2010
STATUS
approved