756872327473domain: NAppears in sequencesa(n) = 6*a(n-1) - a(n-2) - 2 with a(0) = 1, a(1) = 3.at n=16A011900Expansion of (1-3*x) / (1-5*x-5*x^2+x^3).at n=16A108475Numbers k such that k!/m! is a triangular number for some m < k-1.at n=22A227026