OFFSET
1,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
a(25) = rad(25*rad(25)+1) = rad(25*rad(5^2)+1) = rad(25*5+1) = rad(125+1) = rad(126) = rad(2*3*3*7) = 2*3*7 = 42.
MAPLE
rad:= n-> mul(i, i=numtheory[factorset](n)):
a:= n-> rad(n*rad(n)+1):
seq(a(n), n=1..70); # Alois P. Heinz, May 04 2017
MATHEMATICA
rad[n_] := Times @@ FactorInteger[n][[All, 1]]; Table[ rad[n*rad[n] + 1], {n, 1, 54}] (* Jean-François Alcover, Dec 03 2012 *)
PROG
(Haskell)
a078322 = a007947 . a078310
-- Reinhard Zumkeller, Oct 19 2011
(PARI) rad(n)=vecprod(factor(n)[, 1])
a(n)=rad(n*rad(n)+1) \\ Charles R Greathouse IV, Jul 09 2013
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
Reinhard Zumkeller, Nov 23 2002
STATUS
approved