Largest prime that is both left-truncatable and right-truncatable in base n.

Terms

a(0) =23a(1) =11a(2) =67a(3) =839a(4) =37a(5) =1867a(6) =173a(7) =739397a(8) =79a(9) =105691a(10) =379a(11) =37573a(12) =647a(13) =3389a(14) =631a(15) =202715129a(16) =211a(17) =155863a(18) =1283a(19) =787817a(20) =439a(21) =109893629a(22) =577a(23) =4195880189a(24) =1811a(25) =14474071a(26) =379a(27) =21335388527a(28) =2203a(29) =1043557