Numbers of the form k^2+k+1 that are the product of two distinct primes.

Terms

a(0) =21a(1) =57a(2) =91a(3) =111a(4) =133a(5) =183a(6) =381a(7) =553a(8) =703a(9) =813a(10) =871a(11) =993a(12) =1057a(13) =1191a(14) =1261a(15) =1333a(16) =1561a(17) =1641a(18) =1807a(19) =1893a(20) =1981a(21) =2071a(22) =2257a(23) =2353a(24) =2653a(25) =2757a(26) =2863a(27) =3193a(28) =3661a(29) =4033