2647450domain: NAppears in sequencesNumber of alkyls C_{n+15} H_{2n+10} (Phenan) with n carbon atoms.at n=12A000649Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 00101011 or 01010101.at n=21A260920