Number of 6-cycles in the n-Pell graph.

Terms

a(0) =0a(1) =0a(2) =0a(3) =20a(4) =206a(5) =1282a(6) =6302a(7) =26942a(8) =104948a(9) =382444a(10) =1325444a(11) =4417024a(12) =14263474a(13) =44884286a(14) =138222194a(15) =417923290a(16) =1243857480a(17) =3651728760a(18) =10592838440a(19) =30403009612a(20) =86440264694a(21) =243689593114a(22) =681776739174