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A056356
Number of bracelet structures using a maximum of six different colored beads.
7
1, 1, 2, 3, 7, 12, 37, 92, 349, 1308, 5953, 28228, 144587, 760110, 4112548, 22571040, 125410355, 702370208, 3959139804, 22425417824, 127530813841, 727630240536, 4163114812854, 23876534534362, 137228556156385, 790200525479706, 4557943660928233, 26331300028828400
OFFSET
0,3
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]
LINKS
FORMULA
Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.
a(n) = Sum_{k=1..6} A152176(n, k) for n > 0. - Andrew Howroyd, Oct 25 2019
CROSSREFS
Sequence in context: A056156 A112837 A056355 * A084708 A035003 A143879
KEYWORD
nonn
EXTENSIONS
a(0)=1 prepended and terms a(25) and beyond from Andrew Howroyd, Oct 25 2019
STATUS
approved