|
| |
|
|
A085392
|
|
Largest prime factor of greatest proper divisor of n.
|
|
6
| |
|
|
1, 1, 1, 2, 1, 3, 1, 2, 3, 5, 1, 3, 1, 7, 5, 2, 1, 3, 1, 5, 7, 11, 1, 3, 5, 13, 3, 7, 1, 5, 1, 2, 11, 17, 7, 3, 1, 19, 13, 5, 1, 7, 1, 11, 5, 23, 1, 3, 7, 5, 17, 13, 1, 3, 11, 7, 19, 29, 1, 5, 1, 31, 7, 2, 13, 11, 1, 17, 23, 7, 1, 3, 1, 37, 5, 19, 11, 13, 1, 5, 3, 41, 1, 7, 17, 43, 29, 11, 1, 5, 13
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,4
|
|
|
COMMENTS
| Also the largest noncomposite divisor of n. - Jaroslav Krizek, Jun 25 2011.
|
|
|
FORMULA
| a(n) = A006530(A032742(n)). - R. J. Mathar, Jun 26 2011
|
|
|
MAPLE
| A085392 := proc(n) max( op(numtheory[divisors](n) minus {n})) ; A006530(%) ;
end proc:
seq(A085392(n), n=1..50) ; # R. J. Mathar, Jun 26 2011
|
|
|
MATHEMATICA
| PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{gpd = Divisors[n][[ -2]]}, If[gpd == 1, 1, PrimeFactors[gpd][[ -1]] ]]; Table[ If[n == 1, 1, f[n]], {n, 1, 95}]
|
|
|
CROSSREFS
| Cf. A014673, A085393.
Sequence in context: A128487 A056609 A014673 * A089384 A144113 A165416
Adjacent sequences: A085389 A085390 A085391 * A085393 A085394 A085395
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com) and Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 26 2003
|
| |
|
|
