A056439 Number of primitive (period n) step cyclic shifted sequence structures using a maximum of two different symbols.

1, 1, 1, 2, 2, 5, 4, 10, 9, 22, 14, 78, 36, 124, 180, 343, 260, 1329, 804, 3732, 4428, 9742, 8384, 47364, 33778, 108292, 138756, 408244, 331184, 2251604, 1155734

Offset

1,4

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..31.

Formula

Sum mu(d)*A056429(n/d) where d divides n.

Crossrefs

Cf. A002730.

Sequence in context: A292385 A332895 A095057 * A056444 A319925 A112472

Adjacent sequences: A056436 A056437 A056438 * A056440 A056441 A056442

Keyword

nonn

Author

Marks R. Nester

Status

approved