a(n) = Pell(n) * A004018(n) for n>=1 with a(0)=1, where A004018(n) is the number of ways of writing n as a sum of 2 squares.

A205508

a(n) = Pell(n) * A004018(n) for n>=1 with a(0)=1, where A004018(n) is the number of ways of writing n as a sum of 2 squares.

Terms

    a(0) =1a(1) =4a(2) =8a(3) =0a(4) =48a(5) =232a(6) =0a(7) =0a(8) =1632a(9) =3940a(10) =19024a(11) =0a(12) =0a(13) =267688a(14) =0a(15) =0a(16) =1883328a(17) =9093512a(18) =10976840a(19) =0a(20) =127955424a(21) =0a(22) =0a(23) =0a(24) =0a(25) =15740857452a(26) =25334527696a(27) =0a(28) =0a(29) =356483857192

External references