Reversion of Pell numbers A000129(n+1).

Terms

a(0) =1a(1) =-2a(2) =3a(3) =-2a(4) =-6a(5) =28a(6) =-61a(7) =54a(8) =158a(9) =-860a(10) =2062a(11) =-2004a(12) =-5804a(13) =33720a(14) =-84509a(15) =86054a(16) =247862a(17) =-1492908a(18) =3838298a(19) =-4019452a(20) =-11537556a(21) =71101832a(22) =-185868978a(23) =198310460a(24) =567902572a(25) =-3555617432a(26) =9404104764a(27) =-10168382696a(28) =-29069700056a(29) =184127171952