OFFSET
1,3
COMMENTS
a(n) is a divisor of A072513(n).
a(n) = n-1 if and only if n is prime. - Robert Israel, May 26 2015
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = lcm(n-d_1, n-d_2, ..., n-d_k) where d_i are the aliquot divisors of n.
EXAMPLE
a(9) = lcm(9-1, 9-3) = lcm(8, 6) = 24.
MAPLE
f:= n -> ilcm(seq(n-d, d = numtheory:-divisors(n) minus {n})):
map(f, [$ 1 .. 100]); # Robert Israel, May 26 2015
MATHEMATICA
Table[If[n == 1, 1, LCM @@ (n - Most[Divisors[n]])], {n, 50}]
PROG
(PARI) a(n)=lcm(apply(d->if(d<n, n-d, 1), divisors(n))) \\ Charles R Greathouse IV, May 26 2015
(Haskell)
a258324 n = foldl lcm 1 $ map (n -) $ a027751_row n
-- Reinhard Zumkeller, May 27 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Ivan Neretin, May 26 2015
STATUS
approved