A011958 Number of CdI_2 polytypes that repeat after 2n layers.

1, 1, 3, 8, 22, 68, 216, 728, 2513, 8920, 32116, 117240, 431550, 1600734, 5970704, 22381184, 84236890, 318191804, 1205692236, 4581481776, 17452915218, 66637798834, 254960616136, 977346581800, 3753005281872

Offset

1,3

References

T. J. McLarnan, The numbers of polytypes ..., Zeits. Krist. 155, 269-291 (1981).

Links

Table of n, a(n) for n=1..25.

Crossrefs

Sequence in context: A064443 A000732 A092090 * A260661 A171841 A233449

Adjacent sequences: A011955 A011956 A011957 * A011959 A011960 A011961

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved