OFFSET
1,1
COMMENTS
I call these numbers "anti-perfect" (compare with the picture-perfect numbersA069942).
a(7) > 10^12. -Giovanni Resta, Apr 07 2017
EXAMPLE
The proper divisors of 285 are 1, 3, 5, 15, 19, 57, 95, with sum of reverses = 1 + 3 + 5 + 51 + 91 + 75 + 59 = 285. Therefore 285 is anti-perfect.
MATHEMATICA
f[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Do[ If[n == Apply[Plus, Map[f, Drop[Divisors[n], -1]]], Print[n]], {n, 2, 10^7}]
Select[Range[15*10^7], Total[IntegerReverse[Most[Divisors[#]]]]==#&] (* Requires Mathematica version 10 or later *) (* The program takes a long time to run *) (*Harvey P. Dale, Aug 31 2016 *)
CROSSREFS
KEYWORD
base,more,nonn,nice
AUTHOR
Joseph L. Pe, Jul 05 2002
EXTENSIONS
One more term fromFarideh Firoozbakht, Dec 23 2004
a(6) fromGiovanni Resta, Apr 07 2017
STATUS
approved