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A056340
Number of primitive (aperiodic) reversible string structures with n beads using exactly six different colors.
1
0, 0, 0, 0, 0, 1, 12, 142, 1346, 11511, 89974, 662673, 4662574, 31724723, 210361046, 1367510184, 8752976610, 55343946628, 346541488998, 2153041576027, 13292844257186, 81652683460145, 499484958151630
OFFSET
1,7
COMMENTS
A string and its reverse are considered to be equivalent. Permuting the colors 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 6 of A276544.
Cf. A056322.
Sequence in context: A061636 A266177 A135326 * A056330 A158516 A163448
KEYWORD
nonn
STATUS
approved