-2509domain: ZAppears in sequencesExpansion of log(1+log(1+x))/cos(x).at n=6A009316a(n) = 2^n * Sum_{k=0..n} k^p*q^k, where p=2, q=-1/2.at n=15A232603Triangle read by rows: T(n,k) = coefficient of x^(n-k) in Product_{m=0..n-1} (x+(-1)^m*m!), 0 <= k <= n.at n=23A260612