A011953 Number of Barlow packings with group P3m1 that repeat after n layers.

3, 2, 10, 15, 42, 68, 162, 280, 600, 1088, 2214, 4112, 8154, 15366, 30052, 57208, 111166, 212982, 412890, 794688, 1540002, 2974150, 5767344, 11167872, 21680832, 42073640, 81787057, 159005154, 309503502, 602667098

Offset

9,1

Links

Table of n, a(n) for n=9..38.

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

Crossrefs

Sequence in context: A075856 A025520 A099946 * A038519 A192617 A082219

Adjacent sequences: A011950 A011951 A011952 * A011954 A011955 A011956

Keyword

nonn,easy,changed

Author

N. J. A. Sloane.

Status

approved