106850domain: NAppears in sequencesSequence uniquely defined by: n*a(n) = (n-1)*[x^n] B(x) for n>1 with a(0)=a(1)=1, or, equivalently, x*A'(x) = 1+x - B(x) + x*B'(x), where B(x) = series_reversion(x/A(x))/x.at n=6A120957Beach-Williams Pell numbers of type 2pqr (p,q,r primes).at n=12A212076