OFFSET
1,2
COMMENTS
Similar to A308533 where anti-divisors are considered.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..50
EXAMPLE
Divisors of 98 are 1, 2, 7, 14, 49, 98 and their sum is sigma(98) = 171. Then, 127144998 / 171 = 743538.
MAPLE
with(numtheory): P:=proc(q) local n; for n from 1 to q do if frac(parse(cat(op(sort([op(divisors(n))]))))/sigma(n))=0 then
print(n); fi; od; end: P(10^6);
MATHEMATICA
Select[Range[10^6], Mod[FromDigits@ Flatten@ IntegerDigits[#], Total@ #] == 0 &@ Divisors@ # &] (* Michael De Vlieger, Jun 03 2019 *)
PROG
(Magma) k:=1; sol:=[];
for u in [1..10000000] do D:=Divisors(u); conc:=D[1];
for u1 in [2..#D] do a:=#Intseq(conc); a1:=#Intseq(D[u1]); conc:=10^a1*conc+D[u1];
end for;
if conc mod SumOfDivisors(u) eq 0 then sol[k]:=u; k:=k+1; end if;
end for;
sol; // Marius A. Burtea, Jun 01 2019
(PARI) concd(n) = my(d=divisors(n), s=""); fordiv(n, d, s = concat(s, Str(d))); eval(s); \\ A037278
isok(n) = (concd(n) % sigma(n)) == 0; \\ Michel Marcus, Jun 05 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo P. Lava, May 31 2019
EXTENSIONS
a(30)-a(38) from Giovanni Resta, May 31 2019
STATUS
approved