Numbers k such that k^2 + 1 = p*q, p and q prime with p == q (mod k).

Terms

a(0) =3a(1) =8a(2) =12a(3) =144a(4) =1020a(5) =8040a(6) =13860a(7) =34840a(8) =729180a(9) =1728240a(10) =3232060a(11) =17576520a(12) =39279240a(13) =85184880a(14) =117649980a(15) =778689840a(16) =884737920a(17) =1225045140a(18) =1771563420a(19) =3723878100a(20) =3869896140a(21) =4574299320a(22) =7762395960a(23) =12487172640a(24) =14348911860a(25) =14886940920a(26) =21484957560a(27) =24137574780