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A056368
Number of primitive (period n) bracelet structures using exactly four different colored beads.
3
0, 0, 0, 1, 2, 11, 33, 136, 478, 1849, 6845, 26136, 98406, 373977, 1416249, 5380770, 20440250, 77794939, 296384565, 1131009781, 4321964735, 16541268223, 63400061153, 243358777620, 935431121460, 3600520732809
OFFSET
1,5
COMMENTS
Turning over will not create a new bracelet. Permuting the colors of the beads will not change the structure.
REFERENCES
M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
FORMULA
CROSSREFS
Column 4 of A276543.
Cf. A056305.
Sequence in context: A085786 A034128 A034427 * A056359 A088306 A100109
KEYWORD
nonn
STATUS
approved