G.f.: Product_{n>=1} (1 + A002203(n)*x^n + (-1)^n*x^(2*n)) where A002203 is the companion Pell numbers.

A204275

G.f.: Product_{n>=1} (1 + A002203(n)*x^n + (-1)^n*x^(2*n)) where A002203 is the companion Pell numbers.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =26a(4) =57a(5) =222a(6) =698a(7) =2096a(8) =6038a(9) =19730a(10) =58915a(11) =169952a(12) =516024a(13) =1484958a(14) =4397513a(15) =13029558a(16) =37094682a(17) =106442928a(18) =311875984a(19) =879620854a(20) =2522107990a(21) =7229956352a(22) =20398904648a(23) =57543374566a(24) =163053304047a(25) =457604617760

External references