A011958 - OEIS

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A011958

Number of CdI_2 polytypes that repeat after 2n layers.

0

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

(list; graph; refs; listen; history; text; internal format)

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