Product of all primes p such that 2n - p is also prime.

Terms

a(0) =2a(1) =3a(2) =15a(3) =105a(4) =35a(5) =231a(6) =2145a(7) =5005a(8) =4641a(9) =53295a(10) =1616615a(11) =119301a(12) =21505a(13) =7436429a(14) =21489a(15) =57998985a(16) =3038795305a(17) =4123a(18) =13844919a(19) =10393190665a(20) =12838371a(21) =299859855a(23) =12023917269a(24) =70691995a(26) =62483343a(27) =2769282065