A011947 Number of Barlow packings with group P63/mmc(O) that repeat after 4n+2 layers.

1, 1, 3, 7, 14, 31, 63, 123, 255, 511, 1015, 2047, 4092

Offset

0,3

Comments

Apparently identical to A129629.

References

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

Links

Table of n, a(n) for n=0..12.

Formula

Conjecture: a(n) = A045683(2n+1). - R. J. Mathar, Apr 15 2024

Crossrefs

Sequence in context: A173010 A036892 A123707 * A129629 A354463 A223136

Adjacent sequences: A011944 A011945 A011946 * A011948 A011949 A011950

Keyword

nonn,easy,changed

Author

N. J. A. Sloane.

Status

approved