251974domain: NAppears in sequencesG.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k)^2 * x^k*(4-x)^(n-k).at n=8A217461Sum of Fibonacci and tribonacci numbers: a(n) = A000073(n) + A000045(n).at n=23A338192Numbers m that divide the alternating sum Sum_{k=1..m} (-1)^(k+1) * usigma(k).at n=15A379924