Least number d such that 10^n -/+ d form a prime pair.

Terms

a(0) =3a(1) =3a(2) =9a(3) =69a(4) =129a(5) =39a(6) =261a(7) =213a(8) =459a(9) =33a(10) =57a(11) =39a(12) =267a(13) =657a(14) =357a(15) =1377a(16) =3a(17) =387a(18) =1899a(19) =393a(20) =213a(21) =651a(22) =3273a(23) =2733a(24) =3423a(25) =1533a(26) =429a(27) =603a(28) =1131a(29) =1137