Generalized Pellian with 2nd term equal to 6.

Terms

a(0) =1a(1) =6a(2) =13a(3) =32a(4) =77a(5) =186a(6) =449a(7) =1084a(8) =2617a(9) =6318a(10) =15253a(11) =36824a(12) =88901a(13) =214626a(14) =518153a(15) =1250932a(16) =3020017a(17) =7290966a(18) =17601949a(19) =42494864a(20) =102591677a(21) =247678218a(22) =597948113a(23) =1443574444a(24) =3485097001a(25) =8413768446