a(n) = smallest prime of the form 10*K(n) + 1, where K is a number obtained by concatenation of n with itself, or 0 if no such prime exists.
A087403
a(n) = smallest prime of the form 10*K(n) + 1, where K is a number obtained by concatenation of n with itself, or 0 if no such prime exists.
Terms
- a(0) =11a(1) =2221a(2) =31a(3) =41a(4) =555555555551a(5) =61a(6) =71a(7) =881a(8) =991a(9) =101a(11) =1212121a(12) =131a(13) =14141414141a(14) =151a(15) =1616161a(17) =181a(18) =191a(19) =20201a(20) =211
External references
- oeis: A087403