OFFSET
1,2
COMMENTS
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..100
EXAMPLE
a(4) = 12: the divisors of 12 include 4, 1, 2, 3 == 0, 1, 2, 3 (mod 4).
a(5) = 40: the divisors of 40 include 5, 1, 2, 8, 4 == 0, 1, 2, 3, 4 (mod 5).
MAPLE
A[1]:= 1:
for k from 2 to 10^6 do
V:= numtheory:-divisors(k);
for m from 2 to nops(V) do
if not(assigned(A[m])) and (map(`modp`, V, m) = {$0..m-1}) then
A[m]:= k
fi
od
od:
seq(A(n), n=1..49);
MATHEMATICA
a[n_] := a[n] = If[n == 1, 1, For[k = n, True, k += n, If[Union[Mod[Divisors[k], n]] == Range[0, n-1], Return[k]]]];
Table[Print[n, " ", a[n]]; a[n], {n, 1, 100}] (* Jean-François Alcover, Jan 27 2025 *)
PROG
(PARI) a(n) = my(k=1); while (#Set(apply(x->Mod(x, n), divisors(k))) != n, k++); k; \\ Michel Marcus, Jan 27 2025
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Dec 27 2016
STATUS
approved