A298266 Number of nonisomorphic proper colorings of partition multicycle graph using six colors.

1, 6, 21, 15, 56, 90, 40, 126, 315, 120, 240, 165, 252, 840, 720, 840, 600, 990, 624, 462, 1890, 2520, 680, 2240, 3600, 820, 3465, 2475, 3744, 2635, 792, 3780, 6720, 4080, 5040, 12600, 4800, 4920, 9240, 14850, 6600, 13104, 9360, 15810, 11160, 1287, 6930, 15120, 14280, 3060, 10080, 33600, 28800, 17220, 12300, 20790, 51975, 19800, 39600, 13695, 34944, 56160, 24960, 55335, 39525, 66960, 48915, 2002, 11880, 30240, 38080, 18360, 18480, 75600, 100800, 27200, 45920, 73800, 11480, 41580, 138600, 118800, 138600, 99000, 82170, 78624, 196560, 74880, 149760, 102960, 147560, 237150, 105400, 234360, 167400, 293490, 217040

Offset

0,2

Comments

A partition multicycle graph consists of a multiset of cycles with lengths given by the elements of the partition where degenerate cycles on one node are taken to be singletons and on two nodes a pair of nodes connected by an edge. The ordering of the partitions is by traversing antichains in Young's lattice bottom to top, left to right. Isomorphism refers to the automorphisms of the multicycle graph corresponding to the partition, consisting of permutations of cycles of the same length combined with rotations of individual cycles (no dihedral symmetry).

Links

Table of n, a(n) for n=0..96.

Marko Riedel et al., Orbital chromatic polynomials

Formula

For a partition lambda we have the OCP: Product_{p^v in lambda} C(Q_p(k)+v-1, v)

where Q_1(k) = k, Q_2(k) = k(k-1)/2 and for n>=3, Q_n(k) = (1/n) * Sum_{d|n} phi(n/d) P_d(k) with P_d(k) = (k-1)^d + (-1)^d (k-1). Here we have k=6.

Example

Rows are:
    1;
    6;
   21,  15;
   56,  90,  40;
  126, 315, 120, 240, 165;
  252, 840, 720, 840, 600, 990, 624;

Crossrefs

Cf. A297567, A297568, A297569, A297570, A298263, A298264, A298265.

Sequence in context: A170867 A321776 A064929 * A302202 A200831 A184291

Adjacent sequences: A298263 A298264 A298265 * A298267 A298268 A298269

Keyword

nonn,tabf

Author

Marko Riedel, Jan 15 2018

Status

approved