OFFSET
1,1
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
E.g., 14 = 7*2 and 1+4 = 5 is also prime.
MATHEMATICA
Module[{nn=60}, Select[Union[Times@@@Subsets[Prime[Range[nn]], {2}]], PrimeQ[ Total[ IntegerDigits[#]]]&&#<=2Prime[nn]&]] (* Harvey P. Dale, Feb 28 2022 *)
PROG
(PARI) is(n)={bigomega(n)==2 && !issquare(n) && isprime(sumdigits(n))}
select(is, [1..500]) \\ Andrew Howroyd, Jan 05 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 30 2003
EXTENSIONS
Terms a(14) and beyond from Andrew Howroyd, Jan 05 2020
STATUS
approved