a(n) is the smallest prime p whose decimal expansion begins with n and is such that the next prime is p+2n, or -1 if no such prime exists.

A308438

a(n) is the smallest prime p whose decimal expansion begins with n and is such that the next prime is p+2n, or -1 if no such prime exists.

Terms

    a(0) =11a(1) =223a(2) =31a(3) =401a(4) =547a(5) =619a(6) =773a(7) =8581a(8) =9109a(9) =10223a(10) =1129a(11) =12073a(12) =130553a(13) =14563a(14) =150011a(15) =161471a(16) =17257a(17) =18803a(18) =191189a(19) =20809a(20) =210557a(21) =225383a(22) =237091a(23) =240209a(24) =2509433a(25) =2613397a(26) =277429a(27) =283211a(28) =2901649a(29) =308153

External references