A249765 Numbers that divide the concatenation, in descending order, of their anti-divisors.

7, 23957, 56483, 74651, 316782, 13594764, 14473747, 30056837

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Example

Anti-divisors of 7 are and 2, 3, 5 and their concatenation in descending order is 532. Finally, 532 / 7 = 76.

Maple

P:=proc(q) local a, k, n; for n from 3 to q do a:=0;
for k from n-1 by -1 to 2 do if abs((n mod k)-k/2)<1 then a:=a*10^(ilog10(k)+1)+k; fi; od;
if type(a/n, integer) then print(n); fi; od; end: P(10^9);

Crossrefs

Cf. A066272, A069872, A224930, A240265, A249764.

Sequence in context: A351326 A285178 A072050 * A201037 A300200 A156169

Adjacent sequences: A249762 A249763 A249764 * A249766 A249767 A249768

Keyword

nonn,base,hard,more

Author

Paolo P. Lava, Nov 06 2014

Extensions

a(5)-a(8) from Chai Wah Wu, Nov 21 2014

Status

approved