OFFSET
1,1
LINKS
Zak Seidov, Table of n, a(n) for n=1..1616, a(n)<200000
EXAMPLE
a(1)=10 because 10 has only one pair of prime factors (2 and 5) and both 10+2+5 and 10-2-5 (17 and 3) are primes.
MATHEMATICA
a[n_]:={1, 1}==Last/@FactorInteger[n]; b[n_]:=First[First/@FactorInteger[n]]+Last[First/@FactorInteger[n]]; Select[Range[6, 3000], a[#]&&PrimeQ[#-b[#]]&&PrimeQ[#+b[#]]&] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2011 *)
Reap[Do[fi=FactorInteger[n]; la=Last/@fi; If[{1, 1}==la, pq=fi[[1, 1]]+fi[[2, 1]]; If[PrimeQ[n-pq] && PrimeQ[n+pq], Sow[n]]], {n, 6, 200000}]][[2, 1]] (* used to create b-file, Zak Seidov, Mar 04 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Chuck Seggelin (barkeep(AT)plastereddragon.com), Oct 11 2003
STATUS
approved