a(n) = sqrt(2*(P(n)^4 + 16*P(n+1)^4 + P(n+2)^4)), where P() = Pell numbers A000129.

A133417

a(n) = sqrt(2*(P(n)^4 + 16*P(n+1)^4 + P(n+2)^4)), where P() = Pell numbers A000129.

Terms

    a(0) =2a(1) =8a(2) =42a(3) =248a(4) =1442a(5) =8408a(6) =49002a(7) =285608a(8) =1664642a(9) =9702248a(10) =56548842a(11) =329590808a(12) =1920996002a(13) =11196385208a(14) =65257315242a(15) =380347506248

External references