1,2
T. J. McLarnan, The numbers of polytypes ..., Zeits. Krist. 155, 269-291 (1981).
Sequence in context: A136131 A143546 A069066 * A123793 A196420 A199676
Adjacent sequences: A011961 A011962 A011963 * A011965 A011966 A011967
nonn,easy
N. J. A. Sloane (njas(AT)research.att.com).