A quadrisection of A158122: a(n) = A158122(4n+1).

A158213

A quadrisection of A158122: a(n) = A158122(4n+1).

Terms

    a(0) =2a(1) =-4a(2) =40a(3) =-544a(4) =8540a(5) =-145720a(6) =2625648a(7) =-49161024a(8) =947069352a(9) =-18650752400a(10) =373773754912

External references