G.f.: Sum_{n>=0} x^n/Product_{k=1..n} (1 - A002203(k)*x^k + (-1)^k*x^(2*k)), where A002203 is the companion Pell numbers.
A206141
G.f.: Sum_{n>=0} x^n/Product_{k=1..n} (1 - A002203(k)*x^k + (-1)^k*x^(2*k)), where A002203 is the companion Pell numbers.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =8a(4) =26a(5) =67a(6) =216a(7) =555a(8) =1704a(9) =4538a(10) =13320a(11) =35376a(12) =103863a(13) =273792a(14) =783694a(15) =2101835a(16) =5905044a(17) =15745360a(18) =44132278a(19) =117267422a(20) =325136638a(21) =868034994a(22) =2379074541a(23) =6337238658a(24) =17347580484a(25) =46039358056a(26) =125056019725a(27) =332678989816a(28) =898361151760
External references
- oeis: A206141