Primes that remain prime when a single digit 9 is inserted between any two consecutive digits or as the leading or trailing digit.
A215421
Primes that remain prime when a single digit 9 is inserted between any two consecutive digits or as the leading or trailing digit.
Terms
- a(0) =7a(1) =19a(2) =37a(3) =41a(4) =199a(5) =239a(6) =311a(7) =587a(8) =661a(9) =941a(10) =967a(11) =1009a(12) =1997a(13) =4993a(14) =4999a(15) =5393a(16) =5651a(17) =6911a(18) =9109a(19) =9397a(20) =9679a(21) =9829a(22) =19417a(23) =20233a(24) =22549a(25) =27397a(26) =29389a(27) =31387a(28) =39989a(29) =71419
External references
- oeis: A215421