Numbers k such that 10*(10^(k+1) + 10^k - 1) + 7 is prime.

Terms

a(0) =0a(1) =1a(2) =4a(3) =5a(4) =7a(5) =22a(6) =23a(7) =40a(8) =65a(9) =73a(10) =169a(11) =271a(12) =802a(13) =1451a(14) =2623a(15) =4107a(16) =7315a(17) =7583a(18) =7747a(19) =8407a(20) =9841a(21) =19647a(22) =23923a(23) =24825a(24) =30197a(25) =35079