A056440 Number of primitive (period n) step cyclic shifted sequence structures using a maximum of three different symbols.

1, 1, 2, 4, 5, 18, 15, 60, 80, 293, 295, 2217, 1777, 9763, 20632, 58362, 79553, 600696, 567543, 3671674, 6935728, 23785615, 31017007, 246154210, 282456327, 1357925621, 2615206650, 11358502734

Offset

1,3

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..28.

Formula

Sum mu(d)*A056430(n/d) where d divides n.

Crossrefs

Cf. A056420.

Sequence in context: A092051 A065063 A276311 * A101843 A192117 A084592

Adjacent sequences: A056437 A056438 A056439 * A056441 A056442 A056443

Keyword

nonn

Author

Marks R. Nester

Status

approved