50271domain: NAppears in sequencesa(n) = floor(phi*a(n-2)) + a(n-1) where phi is the golden ratio.at n=18A005834Starting positions of strings of four 2's in the decimal expansion of Pi.at n=4A083607Number of length 5 1..(n+2) arrays with no leading partial sum equal to a prime.at n=10A254543