Lucky numbers with size of gaps equal to 6 (upper terms).

Terms

a(0) =21a(1) =31a(2) =43a(3) =49a(4) =93a(5) =99a(6) =105a(7) =111a(8) =141a(9) =169a(10) =201a(11) =211a(12) =267a(13) =273a(14) =303a(15) =327a(16) =367a(17) =391a(18) =399a(19) =415a(20) =421a(21) =427a(22) =483a(23) =495a(24) =517a(25) =535a(26) =559a(27) =651a(28) =679a(29) =685