Numbers k such that 123456789*10^k+1 is prime.

Terms

a(0) =1a(1) =5a(2) =17a(3) =23a(4) =25a(5) =28a(6) =91a(7) =187a(8) =287a(9) =398a(10) =899a(11) =1364a(12) =2921a(13) =5125a(14) =5890a(15) =8780a(16) =14881a(17) =35689a(18) =46669a(19) =71861a(20) =111710