Least k such that k*10^n+1, k*10^n+3, k*10^n+7 and k*10^n+9 are all prime.

Terms

a(0) =4a(1) =1a(2) =1a(3) =13a(4) =676a(5) =283a(6) =14311a(7) =12022a(8) =27346a(9) =14965a(10) =3427a(11) =100942a(12) =12370a(13) =1237a(14) =3274a(15) =42382a(16) =18619a(17) =4570a(18) =457a(19) =434869a(20) =203362a(21) =305491a(22) =213742a(23) =436831a(24) =217198a(25) =168586a(26) =258214a(27) =215737a(28) =1312441a(29) =272848