Diagonal sums of exponential Riordan array [1+x^2*sec(x),x], A166378.

A166380

Diagonal sums of exponential Riordan array [1+x^2*sec(x),x], A166378.

Terms

    a(0) =1a(1) =3a(2) =19a(3) =223a(4) =4667a(5) =160045a(6) =8207125a(7) =587420875a(8) =55869454855

External references