OFFSET
1,1
COMMENTS
Refactorable numbers that are the averages of twin pairs.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[10000], PrimeQ[# - 1] && PrimeQ[# + 1] && Mod[#, DivisorSigma[0, #]] == 0 &] (* T. D. Noe, Jun 03 2013 *)
PROG
(PARI) p=2; forprime(q=3, 1e4, if(q-p==2 && (p+1)%numdiv(p+1)==0, print1(p+1", ")); p=q) \\ Charles R Greathouse IV, Mar 18 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Irina Gerasimova, May 29 2013
STATUS
approved