A056436 Number of step cyclic shifted sequence structures using exactly four different symbols.

0, 0, 0, 1, 1, 11, 13, 83, 162, 930, 1369, 13730, 16421, 124702, 355793, 1356781, 2555043, 25933814, 32931815, 283330733, 720489755, 3308255032, 5763641923, 60874698532, 93543112676, 600086810852

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

A056431(n)-A056430(n).

Crossrefs

Column 4 of A288627.

Cf. A056417.

Sequence in context: A185240 A056446 A023317 * A334930 A089824 A276694

Adjacent sequences: A056433 A056434 A056435 * A056437 A056438 A056439

Keyword

nonn

Author

Marks R. Nester

Status

approved