A143324 Table T(n,k) by antidiagonals. T(n,k) is the number of length n primitive (=aperiodic or period n) k-ary words (n,k >= 1).
1, 2, 0, 3, 2, 0, 4, 6, 6, 0, 5, 12, 24, 12, 0, 6, 20, 60, 72, 30, 0, 7, 30, 120, 240, 240, 54, 0, 8, 42, 210, 600, 1020, 696, 126, 0, 9, 56, 336, 1260, 3120, 4020, 2184, 240, 0, 10, 72, 504, 2352, 7770, 15480, 16380, 6480, 504, 0, 11, 90, 720, 4032, 16800, 46410, 78120, 65280, 19656, 990, 0
Offset: 1
Examples
T(2,3)=6, because there are 6 primitive words of length 2 over 3-letter alphabet {a,b,c}: ab, ac, ba, bc, ca, cb; note that the non-primitive words aa, bb and cc don't belong to the list; secondly note that the words in the list need not be Lyndon words, for example ba can be derived from ab by a cyclic rotation of the positions. Table begins: 1, 2, 3, 4, 5, ... 0, 2, 6, 12, 20, ... 0, 6, 24, 60, 120, ... 0, 12, 72, 240, 600, ... 0, 30, 240, 1020, 3120, ...
Links
- Alois P. Heinz, Antidiagonals n = 1..141, flattened
- C. J. Smyth, A coloring proof of a generalisation of Fermat's little theorem, Amer. Math. Monthly 93, No. 6 (1986), pp. 469-471.
- Lucas Vieira Barbosa, Nonclassical Temporal Correlations Under Finite-Memory Constraints, Doctoral Thesis, Univ. Wien (Austria 2024). See p. 35.
- Index entries for sequences related to Lyndon words
Crossrefs
Programs
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Maple
with(numtheory): f0:= proc(n) option remember; unapply(k^n-add(f0(d)(k), d=divisors(n)minus{n}), k) end; T:= (n,k)-> f0(n)(k); seq(seq(T(n, 1+d-n), n=1..d), d=1..12);
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Mathematica
f0[n_] := f0[n] = Function [k, k^n - Sum[f0[d][k], {d, Complement[Divisors[n], {n}]}]]; t[n_, k_] := f0[n][k]; Table[Table[t[n, 1 + d - n], {n, 1, d}], {d, 1, 12}] // Flatten (* Jean-François Alcover, Dec 12 2013, translated from Maple *)
Formula
T(n,k) = Sum_{d|n} k^d * mu(n/d).
T(n,k) = k^n - Sum_{d
T(n,k) = A143325(n,k) * k.
T(n,k) = A074650(n,k) * n.
So Sum_{d|n} k^d * mu(n/d) == 0 (mod n), this is a generalization of Fermat's little theorem k^p - k == 0 (mod p) for primes p to an arbitrary modulus n (see the Smyth link). - Franz Vrabec, Feb 09 2021
A032164 Number of aperiodic necklaces of n beads of 6 colors; dimensions of free Lie algebras.
1, 6, 15, 70, 315, 1554, 7735, 39990, 209790, 1119720, 6045837, 32981550, 181394535, 1004668770, 5597420295, 31345665106, 176319264240, 995685849690, 5642219252460, 32071565263710, 182807918979777
Offset: 0
Comments
From Petros Hadjicostas, Aug 31 2018: (Start)
For each m >= 1, the CHK[m] transform of sequence (c(n): n>=1) has generating function B_m(x) = (1/m)*Sum_{d|m} mu(d)*C(x^d)^{m/d}, where C(x) = Sum_{n>=1} c(n)*x^n is the g.f. of (c(n): n >= 1). As a result, the CHK transform of sequence (c(n): n >= 1) has generating function B(x) = Sum_{m >= 1} B_m(x) = -Sum_{n >= 1} (mu(n)/n)*log(1 - C(x^n)).
For n, k >= 1, let a_k(n) = number of aperiodic necklaces of n beads of k colors. We then have (a_k(n): n >= 1) = CHK(c_k(n): n >= 1), where c_k(1) = k and c_k(n) = 0 for all n >= 2, with g.f. C_k(x) = Sum_{n >= 1} c_k(n)*x^n = k*x. The g.f. of (a_k(n): n >= 1) is A_k(x) = Sum_{n >= 1} a_k(n)*x^n = -Sum_{n >= 1} (mu(n)/n)*log(1-k*x^n), which is Herbert Kociemba's general formula below (except for the initial term a_k(0) = 1).
For the current sequence, k = 6.
(End)
References
- M. Lothaire, Combinatorics on Words. Addison-Wesley, Reading, MA, 1983, p. 79.
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..1289 (terms 0..200 from T. D. Noe)
- C. G. Bower, Transforms (2)
- E. N. Gilbert and J. Riordan, Symmetry types of periodic sequences, Illinois J. Math., 5 (1961), 657-665.
- Y. Puri and T. Ward, Arithmetic and growth of periodic orbits, J. Integer Seqs., Vol. 4 (2001), #01.2.1.
- F. Ruskey, Necklaces, Lyndon words, De Bruijn sequences, etc.
- F. Ruskey, Necklaces, Lyndon words, De Bruijn sequences, etc. [Cached copy, with permission, pdf format only]
- G. Viennot, Algèbres de Lie Libres et Monoïdes Libres, Lecture Notes in Mathematics 691, Springer Verlag 1978.
- Index entries for sequences related to Lyndon words
Programs
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Mathematica
f[d_] := MoebiusMu[d]*6^(n/d)/n; a[n_] := Total[f /@ Divisors[n]]; a[0] = 1; Table[a[n], {n, 0, 20}](* Jean-François Alcover, Nov 07 2011 *) mx=40;f[x_,k_]:=1-Sum[MoebiusMu[i] Log[1-k*x^i]/i,{i,1,mx}];CoefficientList[Series[f[x,6],{x,0,mx}],x] (* Herbert Kociemba, Nov 25 2016 *)
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PARI
a(n) = if (n==0, 1, sumdiv(n, d, moebius(d)*6^(n/d)/n)); \\ Michel Marcus, Dec 01 2015
Formula
"CHK" (necklace, identity, unlabeled) transform of 6, 0, 0, 0...
a(n) = Sum_{d|n} mu(d)*6^(n/d)/n, for n>0.
G.f.: k=6, 1 - Sum_{i>=1} mu(i)*log(1 - k*x^i)/i. - Herbert Kociemba, Nov 25 2016
A054718 Number of ternary sequences with primitive period n.
1, 3, 6, 24, 72, 240, 696, 2184, 6480, 19656, 58800, 177144, 530640, 1594320, 4780776, 14348640, 43040160, 129140160, 387400104, 1162261464, 3486725280, 10460350992, 31380882456, 94143178824, 282428998560, 847288609200, 2541864234000, 7625597465304
Offset: 0
Keywords
Comments
Equivalently, output sequences with primitive period n from a simple cycling shift register.
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..2095 (terms 0..650 from Alois P. Heinz)
- E. N. Gilbert and J. Riordan, Symmetry types of periodic sequences, Illinois J. Math., 5 (1961), 657-665.
Programs
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Maple
with(numtheory): a:= n-> `if`(n=0, 1, add(mobius(d)*3^(n/d), d=divisors(n))): seq(a(n), n=0..30); # Alois P. Heinz, Oct 21 2012
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Mathematica
a[0] = 1; a[n_] := Sum[MoebiusMu[d]*3^(n/d), {d, Divisors[n]}]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Mar 11 2014, after Alois P. Heinz *)
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PARI
a(n) = if(n==0,1,sumdiv(n,d, moebius(d) * 3^(n/d) )); \\ Joerg Arndt, Apr 14 2013
Formula
a(n) = Sum_{d|n} mu(d)*3^(n/d).
a(0) = 1, a(n) = n * A027376(n).
a(n) = 3 * A034741(n).
G.f.: 1 + 3 * Sum_{k>=1} mu(k) * x^k / (1 - 3*x^k). - Ilya Gutkovskiy, Apr 14 2021
A056271 Number of primitive (aperiodic) words of length n which contain exactly six different symbols.
0, 0, 0, 0, 0, 720, 15120, 191520, 1905120, 16435440, 129230640, 953028720, 6711344640, 45674173440, 302899156560, 1969146930240, 12604139926560, 79694818842240, 499018753280880, 3100376788241040
Offset: 1
Keywords
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]
Formula
Sum mu(d)*A000920(n/d) where d|n.
A056277 Number of primitive (aperiodic) word structures of length n using a 6-ary alphabet.
1, 1, 4, 13, 51, 197, 875, 4096, 20643, 109246, 601491, 3402911, 19628063, 114699438, 676207572, 4010086352, 23874362199, 142508702805, 852124263683, 5101098123207, 30560194492576, 183176169456214
Offset: 1
Keywords
Comments
Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same 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]
Crossrefs
Cf. A054721.
Formula
sum mu(d)*A056273(n/d) where d|n and n>0.
A363916 Array read by descending antidiagonals. A(n, k) = Sum_{d=0..k} A363914(k, d) * n^d.
1, 0, 1, 0, 1, 1, 0, 0, 2, 1, 0, 0, 2, 3, 1, 0, 0, 6, 6, 4, 1, 0, 0, 12, 24, 12, 5, 1, 0, 0, 30, 72, 60, 20, 6, 1, 0, 0, 54, 240, 240, 120, 30, 7, 1, 0, 0, 126, 696, 1020, 600, 210, 42, 8, 1, 0, 0, 240, 2184, 4020, 3120, 1260, 336, 56, 9, 1
Offset: 0
Comments
Examples
Array A(n, k) starts: [0] 1, 0, 0, 0, 0, 0, 0, 0, 0, ... A000007 [1] 1, 1, 0, 0, 0, 0, 0, 0, 0, ... A019590 [2] 1, 2, 2, 6, 12, 30, 54, 126, 240, ... A027375 [3] 1, 3, 6, 24, 72, 240, 696, 2184, 6480, ... A054718 [4] 1, 4, 12, 60, 240, 1020, 4020, 16380, 65280, ... A054719 [5] 1, 5, 20, 120, 600, 3120, 15480, 78120, 390000, ... A054720 [6] 1, 6, 30, 210, 1260, 7770, 46410, 279930, 1678320, ... A054721 [7] 1, 7, 42, 336, 2352, 16800, 117264, 823536, 5762400, ... A218124 [8] 1, 8, 56, 504, 4032, 32760, 261576, 2097144, 16773120, ... A218125 A000012|A002378| A047928 | A218130 | A218131 A001477,A007531, A061167, A133499, (diagonal A252764) . Triangle T(n, k) starts: [0] 1; [1] 0, 1; [2] 0, 1, 1; [3] 0, 0, 2, 1; [4] 0, 0, 2, 3, 1; [5] 0, 0, 6, 6, 4, 1; [6] 0, 0, 12, 24, 12, 5, 1; [7] 0, 0, 30, 72, 60, 20, 6, 1; [8] 0, 0, 54, 240, 240, 120, 30, 7, 1;
Links
- E. N. Gilbert and J. Riordan, Symmetry types of periodic sequences, Illinois J. Math., 5 (1961), 657-665.
Crossrefs
Programs
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Maple
A363916 := (n, k) -> local d; add(A363914(k, d) * n^d, d = 0 ..k): for n from 0 to 9 do seq(A363916(n, k), k = 0..8) od;
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SageMath
def A363916(n, k): return sum(A363914(k, d) * n^d for d in range(k + 1)) for n in range(9): print([A363916(n, k) for k in srange(9)]) def T(n, k): return A363916(k, n - k)
Comments