A048142 Number of symmetrical planar partitions of n: planar partitions (A000219) that when regarded as 3-D objects have only a threefold axis of symmetry, i.e., C3 symmetry.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 2, 2, 0, 3, 3, 0, 5, 6, 0, 7, 9, 0, 11, 16, 1, 14, 23, 2, 20, 36, 4, 27, 52, 7, 37, 78, 13, 48, 111, 21, 65, 163, 36, 83, 227, 56, 109, 322, 89, 139, 444, 135, 179, 618, 207, 226, 841, 305, 288, 1151, 453, 361

Offset

1,19

Comments

Only one of the pair left-handed, right-handed, is enumerated.

Links

Wouter Meeussen, Table of n, a(n) for n = 1..202

Formula

a(n) = (A096419(n) - A048141(n))/2.

Example

The plane partitions {{3, 2, 2}, {3, 1}, {1, 1}} and {{3, 2, 2}, {3, 2}, {1, 1}} have C3 symmetry.

Crossrefs

Cf. A000219, A000784, A000785, A000786, A005987, A048141, A051056-A051061, A096419.

Sequence in context: A128615 A087508 A095731 * A071426 A288530 A295675

Adjacent sequences: A048139 A048140 A048141 * A048143 A048144 A048145

Keyword

nice,nonn

Author

Wouter Meeussen

Status

approved