OFFSET
1,2
COMMENTS
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..3000
EXAMPLE
Divisors of 1111: 1, 11, 101, 1111.
MATHEMATICA
Select[Table[n, {n, 20000}], ! PrimeQ[#] && Union[First /@ IntegerDigits[Divisors[#]]] == {1} && Union[Last /@ IntegerDigits[Divisors[#]]] == {1} &] (* Vladimir Joseph Stephan Orlovsky, Feb 26 2012 *)
d1Q[n_]:=Module[{idn=IntegerDigits[n]}, First[idn]==Last[idn]==1]; Select[ Range[1, 20000, 10], !PrimeQ[#]&&Count[Divisors[#], _?d1Q] == DivisorSigma[ 0, #]&] (* Harvey P. Dale, Nov 23 2012 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Feb 24 2012
STATUS
approved