OFFSET
3,1
COMMENTS
LINKS
Seiichi Manyama, Table of n, a(n) for n = 3..10000
MAPLE
antidivisors := proc(n)
local a, k;
a := {} ;
for k from 2 to n-1 do
if abs((n mod k)- k/2) < 1 then
a := a union {k} ;
end if;
end do:
a ;
end proc:
A066481 := proc(n)
if n < 3 then
return 0;
else
sort(convert(antidivisors(n), list)) ;
op(-1, %) ;
end if;
end proc: # R. J. Mathar, Mar 15 2013
MATHEMATICA
antid[n_] := Select[ Union[ Join[ Select[ Divisors[2n - 1], OddQ[ # ] && # != 1 &], Select[ Divisors[2n + 1], OddQ[ # ] && # != 1 &], 2n/Select[ Divisors[2*n], OddQ[ # ] && # != 1 &]]], # < n & ]; Table[ Last[ antid[n]], {n, 3, 100} ]
PROG
(PARI) a(n)=2*n\/3 \\ Charles R Greathouse IV, Feb 27 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jan 02 2002
STATUS
approved