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A051119
a(n) = n/p^k, where p = largest prime dividing n and p^k = highest power of p dividing n.
21
1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 4, 1, 2, 3, 1, 1, 2, 1, 4, 3, 2, 1, 8, 1, 2, 1, 4, 1, 6, 1, 1, 3, 2, 5, 4, 1, 2, 3, 8, 1, 6, 1, 4, 9, 2, 1, 16, 1, 2, 3, 4, 1, 2, 5, 8, 3, 2, 1, 12, 1, 2, 9, 1, 5, 6, 1, 4, 3, 10, 1, 8, 1, 2, 3, 4, 7, 6, 1, 16, 1, 2, 1, 12, 5, 2, 3, 8, 1, 18, 7, 4, 3, 2, 5, 32, 1, 2, 9, 4, 1
OFFSET
1,6
FORMULA
a(n) = n/A053585(n).
EXAMPLE
a(36) = 4 because 36/3^2 = 4, 3^2 is highest power dividing 36 of largest prime dividing 36.
a(50) = 50/5^2 = 2.
MATHEMATICA
f[n_]:=Module[{c=Last[FactorInteger[n]]}, n/First[c]^Last[c]]; Array[ f, 110] (* Harvey P. Dale, Oct 14 2011 *)
PROG
(Python)
from sympy import factorint, primefactors
def a053585(n):
if n==1: return 1
p = primefactors(n)[-1]
return p**factorint(n)[p]
def a(n): return n/a053585(n) # Indranil Ghosh, May 19 2017
(PARI) a(n) = if(n>1, my(f=factor(n)); n/f[#f~, 1]^f[#f~, 2], 1); \\ Michel Marcus, Jan 10 2025
CROSSREFS
Cf. A053585.
Sequence in context: A378887 A353688 A353666 * A159269 A186728 A158298
KEYWORD
nonn,easy,nice
AUTHOR
EXTENSIONS
More terms from James A. Sellers, Jan 21 2000
STATUS
approved