A056375 Number of step shifted (decimated) sequences using a maximum of six different symbols.

6, 36, 126, 756, 2016, 23976, 46956, 435456, 1683576, 15128856, 36284472, 547204896, 1088416056, 13060989936, 58782164616, 352913845536, 1057916846196, 16926689693376, 33853322280036, 457078896068256, 1828085963706576

Offset

1,1

Comments

See A056371 for an explanation of step shifts.

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

G. C. Greubel, Table of n, a(n) for n = 1..1275

R. C. Titsworth, Equivalence classes of periodic sequences, Illinois J. Math., 8 (1964), 266-270.

Formula

The cycle index is implicit in Titsworth.

Sequences A056372-A056375 fit a general formula, implemented in PARI/GP as follows: { a(m,n) = sum(k=1, n, if(gcd(k, n)==1, m^sumdiv(n, d, eulerphi(d)/znorder(Mod(k, d))), 0); ) / eulerphi(n) }. - Max Alekseyev, Nov 08 2007

Mathematica

a[m_, n_] := (1/EulerPhi[n])*Sum[If[GCD[k, n] == 1, m^DivisorSum[n, EulerPhi[#]/MultiplicativeOrder[k, #] &], 0], {k, 1, n}]; Table[a[6, n], {n, 1, 21}] (* Jean-François Alcover, Dec 04 2015 *)

Crossrefs

Cf. A056414.

A row or column of A132191.

Sequence in context: A061707 A253945 A331576 * A360588 A321579 A364429

Adjacent sequences: A056372 A056373 A056374 * A056376 A056377 A056378

Keyword

nonn

Author

Marks R. Nester

Extensions

More terms from Max Alekseyev, Nov 08 2007

Status

approved