G.f.: exp( Sum_{n>=1} sigma(n)*A002203(n)*x^n/n ) where A002203 is the companion Pell numbers.

A203534

G.f.: exp( Sum_{n>=1} sigma(n)*A002203(n)*x^n/n ) where A002203 is the companion Pell numbers.

Terms

    a(0) =1a(1) =2a(2) =11a(3) =38a(4) =156a(5) =516a(6) =1991a(7) =6434a(8) =23065a(9) =75132a(10) =255335a(11) =816480a(12) =2724245a(13) =8570794a(14) =27763807a(15) =87057596a(16) =276339126a(17) =855374534a(18) =2681503010a(19) =8218321006a(20) =25421912010a(21) =77383062314a(22) =236519199902a(23) =714226056554

External references