OFFSET
1,2
COMMENTS
Except for 3, all primes are in this sequence. - Alonso del Arte, Jun 13 2014
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
A099475(a(n)) = 0.
EXAMPLE
10 is in the sequence because its divisors are 1, 2, 5, 10, none of which is 2 less than another.
11 is in the sequence as are all primes other than 3.
12 is not in the sequence because its divisors are 1, 2, 3, 4, 6, 12, of which 2 and 4 are 2 less than another divisor.
MATHEMATICA
twinDivsQ[n_] := Union[ IntegerQ[ # ] & /@ (n/(Divisors[n] + 2))][[ -1]] == True; Select[ Range[133], !twinDivsQ[ # ] &] (* Robert G. Wilson v, Jun 09 2005 *)
d2noQ[n_]:=Module[{d=Divisors[n]}, Intersection[d, d+2]=={}]; Select[ Range[ 150], d2noQ] (* Harvey P. Dale, Feb 15 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 18 2004
STATUS
approved