OFFSET
1,2
COMMENTS
Let p be the largest prime dividing n, a(n) is the largest power of p dividing n.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1000 terms from T. D. Noe)
FORMULA
EXAMPLE
a(42)=7 because 42=2*3*7, a(144)=9 because 144=16*9=2^4*3^2.
MAPLE
a:= n-> `if`(n=1, 1, (i->i[1]^i[2])(sort(ifactors(n)[2])[-1])):
seq(a(n), n=1..100); # Alois P. Heinz, Nov 03 2023
MATHEMATICA
Table[Power @@ Last @ FactorInteger @ n, {n, 79}] (* Jean-François Alcover, Apr 01 2011 *)
PROG
(Haskell)
a053585 = last . a141809_row -- Reinhard Zumkeller, Jan 29 2013
(PARI) a(n)=if(n>1, my(f=factor(n)); f[#f~, 1]^f[#f~, 2], 1) \\ Charles R Greathouse IV, Nov 10 2015
(Python)
from sympy import factorint, primefactors
def a(n):
if n==1: return 1
p = primefactors(n)[-1]
return p**factorint(n)[p] # Indranil Ghosh, May 19 2017
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
Frederick Magata (frederick.magata(AT)uni-muenster.de), Jan 19 2000
EXTENSIONS
More terms from Andrew Gacek (andrew(AT)dgi.net), Apr 20 2000
STATUS
approved