OFFSET
1,1
COMMENTS
A073930 is a subset of this sequence.
LINKS
Paolo P. Lava, Table of n, a(n) for n = 1..200
EXAMPLE
Anti-divisors of 5 are 2, 3 whose sum is 5.
Anti-divisors of 41 are 2, 3, 9, 27 whose sum is 41.
Anti-divisors of 64 are 3, 43 whose sum is 46 that is a permutation of the digit of 64.
MAPLE
with(numtheory):P:=proc(q) local a, b, j, k, ok, n, p;
for n from 1 to q do k:=0; j:=n;
while j mod 2 <> 1 do k:=k+1; j:=j/2; od;
a:=sigma(2*n+1)+sigma(2*n-1)+sigma(n/2^k)*2^(k+1)-6*n-2;
if ilog10(n)=ilog10(a) then j:=sort(convert(n, base, 10)); a:=sort(convert(a, base, 10)); ok:=1;
for k from 1 to nops(a) do if j[k]<>a[k] then ok:=0; break;
fi; od; if ok=1 then print(n); fi; fi; od; end: P(10^9);
MATHEMATICA
ad[n_] := Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)]; Select[Range@ 5000, SameQ[DigitCount@ #, DigitCount[Total[ad@ #]]] &] (* Michael De Vlieger, Jun 10 2015 *)
PROG
(Python)
from sympy.ntheory.factor_ import antidivisors
A258786_list = [n for n in range(1, 10**5) if sorted(str(n)) == sorted(str(sum(antidivisors(n))))] # Chai Wah Wu, Jun 11 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo P. Lava, Jun 10 2015
STATUS
approved