A056393 Number of step shifted (decimated) sequence structures using a maximum of four different symbols.

1, 2, 4, 11, 17, 107, 131, 811, 1893, 11107, 17599, 179371, 233449, 1866057, 5603787, 22469291, 44744047, 477262537, 636308685, 5732457131, 15272176697, 73301054891, 133274359129, 1466413263531

Offset

1,2

Comments

See A056371 for an explanation of step shifts. 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..24.

Formula

Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.

a(n) = Sum_{k=1..4} A288620(n, k). - Andrew Howroyd, Jun 13 2017

Crossrefs

Cf. A056373, A288620.

Sequence in context: A283357 A182642 A218911 * A319417 A056394 A056395

Adjacent sequences: A056390 A056391 A056392 * A056394 A056395 A056396

Keyword

nonn

Author

Marks R. Nester

Status

approved