A011956 Barlow packings with group R3m that repeat after 3n layers.

1, 2, 4, 10, 21, 42, 84, 164, 322, 620

Offset

7,2

Links

Table of n, a(n) for n=7..16.

T. J. McLarnan, The numbers of polytypes in close-packings and related structures, Zeits. Krist. 155, 269-291 (1981).

Crossrefs

Cf. A011768.

Sequence in context: A175204 A215533 A128461 * A371358 A018003 A328692

Adjacent sequences: A011953 A011954 A011955 * A011957 A011958 A011959

Keyword

nonn,easy,more

Author

N. J. A. Sloane

Extensions

Name and offset corrected by Andrey Zabolotskiy, Feb 14 2024

Status

approved