a(n) equals the coefficient of x^(2*n)*y^n/(2*n)! in cos((x - x*y)/2) / cos((x + x*y)/2).
A272482
a(n) equals the coefficient of x^(2*n)*y^n/(2*n)! in cos((x - x*y)/2) / cos((x + x*y)/2).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =25a(4) =455a(5) =14301a(6) =683067a(7) =45956625a(8) =4136759055a(9) =479777869285
External references
- oeis: A272482