# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a011958 Showing 1-1 of 1 %I A011958 #5 Mar 30 2012 16:45:51 %S A011958 1,1,3,8,22,68,216,728,2513,8920,32116,117240,431550,1600734,5970704, %T A011958 22381184,84236890,318191804,1205692236,4581481776,17452915218, %U A011958 66637798834,254960616136,977346581800,3753005281872 %N A011958 Number of CdI_2 polytypes that repeat after 2n layers. %D A011958 T. J. McLarnan, The numbers of polytypes ..., Zeits. Krist. 155, 269-291 (1981). %K A011958 nonn,easy %O A011958 1,3 %A A011958 _N. J. A. Sloane_. # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE