A056446 Number of primitive (period n) step cyclic shifted sequence structures using exactly four different symbols.

0, 0, 0, 1, 1, 11, 13, 82, 162, 929, 1369, 13718, 16421, 124689, 355792, 1356698, 2555043, 25933641, 32931815, 283329802, 720489742, 3308253663, 5763641923, 60874684720, 93543112675, 600086794431

Offset

1,6

Comments

See A056371 for an explanation of step shifts. Under step cyclic shifts, abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. Permuting the symbols 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..26.

Formula

A056441(n)-A056440(n).

Crossrefs

Cf. A056426.

Sequence in context: A226242 A116436 A185240 * A023317 A056436 A334930

Adjacent sequences: A056443 A056444 A056445 * A056447 A056448 A056449

Keyword

nonn

Author

Marks R. Nester

Status

approved