501774317241domain: NAppears in sequencesa(n) = T(2n+1), where T(n) are the tribonacci numbers A000073.at n=23A073717a(n) = 7*a(n-1) - 5*a(n-2) + a(n-3), with initial values a(0) = a(1) = 1, a(2)=4.at n=16A192806