A056339 Number of primitive (aperiodic) reversible string structures with n beads using exactly five different colors.

0, 0, 0, 0, 1, 9, 76, 542, 3523, 21392, 123680, 690541, 3756151, 20042513, 105394295, 548123440, 2826435403, 14479201301, 73794961960, 374603863517, 1895632969275, 9568915248589, 48208452866816

Offset

1,6

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]

Links

Table of n, a(n) for n=1..23.

Formula

A056334(n)-A056333(n).

Crossrefs

Column 5 of A276544.

Cf. A056321.

Sequence in context: A274657 A255931 A319957 * A056329 A190982 A082677

Adjacent sequences: A056336 A056337 A056338 * A056340 A056341 A056342

Keyword

nonn

Author

Marks R. Nester

Status

approved