A277427 -id:A277427 - cp's OEIS frontend

A060223 Number of orbits of length n under the map whose periodic points are counted by A000670.

1, 1, 1, 4, 18, 108, 778, 6756, 68220, 787472, 10224702, 147512052, 2340963570, 40527565260, 760095923082, 15352212731820, 332228417589720, 7668868648772700, 188085259069430744, 4884294069438337428, 133884389812214097774, 3863086904690670182596

Offset: 0

Thomas Ward, Mar 21 2001

From Gus Wiseman, Oct 14 2016: (Start)
A finite sequence is normal if it spans an initial interval of positive integers. The *-product of two or more finite sequences is defined to be the lexicographically minimal sequence obtainable by shuffling the sequences together. For example, (2 2 1) * (2 1 3) = (2 1 2 2 1 3). If Q is the set of compositions (finite sequences of positive integers) then (Q,*) is an Abelian group freely generated by a set P of prime sequences. The number of normal prime sequences of length n is equal to a(n). See example 2 and Mathematica program 2.
If N is the species (endofunctor over the category of finite sets and permutations) of unlabeled necklaces and N(S) represents the set of all non-isomorphic primitive necklaces of length n=|S|, then the numbers |N(S)| are equal to the numbers a(|S|) for any finite set S. This is because the number of orderless *-factorizations (see A034691 and A269134) of any finite sequence q is equal to the number of multiset partitions (see A007716 and A255906) of the multiset of prime factors of q. (End)

			a(5) = 108 since A000670(5) is 541 and A000670(1) is 1, so there must be (541-1)/5 = 108 orbits of length 5.
From _Gus Wiseman_, Oct 14 2016: (Start)
The a(4) = 18 normal prime sequences are the columns:
[2 2 2 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4]
[1 2 2 1 1 1 2 2 2 2 3 3 1 1 2 2 3 3]
[1 1 2 1 2 2 1 1 2 3 1 2 2 3 1 3 1 2]
[1 1 1 2 1 2 1 2 1 1 2 1 3 2 3 1 2 1].
The symmetric function A(x_1,x_2,x_3,...) expanded in terms of monomial symmetric functions m(y) (indexed by integer partitions y) is equal to:
A = m(1) +
    m(11) +
    (2*m(21) + 2*m(111) +
    (m(22) + 2*m(31) + 9*m(211) + 6*m(1111)) +
    (4*m(32) + 2*m(41) + 18*m(221) + 12*m(311) + 48*m(2111) + 24*m(11111)) +
    (3*m(33) + 4*m(42) + 2*m(51) + 14*m(222) + 60*m(321) + 15*m(411) + 180*m(2211) + 80*m(3111) + 300*m(21111) + 120*m(111111)) + ... (End)

Alois P. Heinz, Table of n, a(n) for n = 0..200
Yash Puri and Thomas Ward, A dynamical property unique to the Lucas sequence, Fibonacci Quarterly, Volume 39, Number 5 (November 2001), pp. 398-402.
Y. Puri and T. Ward, Arithmetic and growth of periodic orbits, J. Integer Seqs., Vol. 4 (2001), #01.2.1.
T. Ward, Exactly realizable sequences

Cf. A000670, A034691 (multisets of compositions), A269134, A007716, A277427, A215474, A255906.

Row sums of A254040.

a[n_] := DivisorSum[n, MoebiusMu[#] HurwitzLerchPhi[1/2, -n/#, 0]/2 &] / n; a[0] = 1; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Mar 30 2016 *)
thufbin[{},b_List]:=b;thufbin[a_List,{}]:=a;thufbin[a_List]:=a;
thufbin[{x_,a___},{y_,b___}]:=Switch[Ordering[If[x=!=y,{x,y},{thufbin[{a},{x,b}],thufbin[{x,a},{b}]}]],{1,2},Prepend[thufbin[{a},{y,b}],x],{2,1},Prepend[thufbin[{x,a},{b}],y]];
thufbin[a_List,b_List,c__List]:=thufbin[a,thufbin[b,c]];
priseqs[n_]:=Fold[Select,Tuples[Range[n],n],{Union[#]===Range[First[#]]&,Function[q,Select[Table[List[Take[q,{1,j}],Take[q,{j+1,n}]],{j,1,n-1}],thufbin@@Sort[#]===q&,1]==={}]}];
Table[Length[priseqs[n]],{n,1,7}] (* Gus Wiseman, Oct 14 2016 *)

\\ here b(n) is A000670
b(n)={polcoeff(serlaplace(1/(2-exp(x+O(x*x^n)))), n)}
a(n)={if(n<1, n==0, sumdiv(n, d, moebius(d)*b(n/d))/n)} \\ Andrew Howroyd, Dec 12 2017

a(n) = (1/n)* Sum_{d|n} mu(d)*A000670(n/d) for n > 0, where mu is A008683, the Moebius function. - Edited by Michel Marcus, Mar 30 2016
Let A = Sum_{q in P} Prod_i x_{q_i} = Sum_y c_y m(y) be the symmetric function whose coefficient of m(y) is equal to the number of permutations of the normal multiset [k]^y that belong to P, where the multiplicity of i in [k]^y is defined to be y_i. Then a(n) is the sum of c_y taken over all integer partitions of n. See example 3. - Gus Wiseman, Oct 14 2016
a(n) = Sum_{d|n} mu(d) * A019536(n/d) for n >= 1. - Petros Hadjicostas, Aug 19 2019

More terms from Alois P. Heinz, Jan 23 2015

A296372 Triangle read by rows: T(n,k) is the number of normal sequences of length n whose standard factorization into Lyndon words (aperiodic necklaces) has k factors.

Original entry on oeis.org

1, 1, 2, 4, 5, 4, 18, 31, 18, 8, 108, 208, 153, 56, 16, 778, 1700, 1397, 616, 160, 32, 6756, 15980, 14668, 7197, 2196, 432, 64, 68220, 172326, 171976, 93293, 31564, 7208, 1120, 128

Offset: 1

Gus Wiseman, Dec 11 2017

A finite sequence is normal if its union is an initial interval of positive integers.

			The T(3,2) = 5 normal sequences are {2,1,2}, {1,2,1}, {2,1,3}, {2,3,1}, {3,1,2}.
Triangle begins:
     1;
     1,     2;
     4,     5,     4;
    18,    31,    18,     8;
   108,   208,   153,    56,    16;
   778,  1700,  1397,   616,   160,    32;
  6756, 15980, 14668,  7197,  2196,   432,    64;

Andrew Howroyd, Rows n = 1..50 of triangle, flattened
Wikipedia, Lyndon word: Standard factorization

Row sums are A000670.
First column is A060223.
Cf. A000740, A001045, A008965, A019536, A059966, A074650, A185700, A228369, A232472, A277427, A281013, A296373.

neckQ[q_]:=Array[OrderedQ[{q,RotateRight[q,#]}]&,Length[q]-1,1,And];
aperQ[q_]:=UnsameQ@@Table[RotateRight[q,k],{k,Length[q]}];
qit[q_]:=If[#===Length[q],{q},Prepend[qit[Drop[q,#]],Take[q,#]]]&[Max@@Select[Range[Length[q]],neckQ[Take[q,#]]&&aperQ[Take[q,#]]&]];
allnorm[n_]:=Function[s,Array[Count[s,y_/;y<=#]+1&,n]]/@Subsets[Range[n-1]+1];
Table[Length[Select[Join@@Permutations/@allnorm[n],Length[qit[#]]===k&]],{n,5},{k,n}]

\\ here U(n,k) is A074650(n,k).
EulerMT(u)={my(n=#u, p=x*Ser(u), vars=variables(p)); Vec(exp( sum(i=1, n, substvec(p + O(x*x^(n\i)), vars, apply(v->v^i,vars))/i ))-1)}
U(n,k)={sumdiv(n, d, moebius(n/d) * k^d)/n}
A(n)={[Vecrev(p/y) | p<-sum(k=1, n, EulerMT(vector(n, n, y*U(n,k)))*sum(j=k, n, (-1)^(k-j)*binomial(j,k)))]}
{ my(T=A(10)); for(n=1, #T, print(T[n])) } \\ Andrew Howroyd, Dec 08 2018

Example and program corrected by Gus Wiseman, Dec 08 2018

A281013 Tetrangle T(n,k,i) = i-th part of k-th prime composition of n.

Original entry on oeis.org

1, 2, 2, 1, 3, 2, 1, 1, 3, 1, 4, 2, 1, 1, 1, 2, 2, 1, 3, 1, 1, 3, 2, 4, 1, 5, 2, 1, 1, 1, 1, 2, 2, 1, 1, 3, 1, 1, 1, 3, 1, 2, 3, 2, 1, 4, 1, 1, 4, 2, 5, 1, 6, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 2, 2, 1, 3, 1, 1, 1, 1, 3, 1, 1, 2, 3, 1, 2, 1, 3, 2, 1, 1, 3, 2, 2, 3, 3, 1, 4, 1, 1, 1, 4, 1, 2, 4, 2, 1, 4, 3, 5, 1, 1, 5, 2, 6, 1, 7

Offset: 1

Gus Wiseman, Jan 12 2017

The *-product of two or more finite sequences is defined to be the lexicographically minimal sequence obtainable by shuffling them together. Every finite positive integer sequence has a unique *-factorization using prime compositions P = {(1), (2), (21), (3), (211), ...}. See A060223 and A228369 for details.

These are co-Lyndon compositions, ordered first by sum and then lexicographically. - Gus Wiseman, Nov 15 2019

			The prime factorization of (1, 1, 4, 2, 3, 1, 5, 5) is: (11423155) = (1)*(1)*(5)*(5)*(4231). The prime factorizations of the initial terms of A000002 are:
             (1) = (1)
            (12) = (1)*(2)
           (122) = (1)*(2)*(2)
          (1221) = (1)*(221)
         (12211) = (1)*(2211)
        (122112) = (1)*(2)*(2211)
       (1221121) = (1)*(221121)
      (12211212) = (1)*(2)*(221121)
     (122112122) = (1)*(2)*(2)*(221121)
    (1221121221) = (1)*(221)*(221121)
   (12211212212) = (1)*(2)*(221)*(221121)
  (122112122122) = (1)*(2)*(2)*(221)*(221121).
Read as a sequence:
(1), (2), (21), (3), (211), (31), (4), (2111), (221), (311), (32), (41), (5).
Read as a triangle:
(1)
(2)
(21), (3)
(211), (31), (4)
(2111), (221), (311), (32), (41), (5).
Read as a sequence of triangles:
1    2    2 1    2 1 1    2 1 1 1    2 1 1 1 1    2 1 1 1 1 1
          3      3 1      2 2 1      2 2 1 1      2 1 2 1 1
                 4        3 1 1      3 1 1 1      2 2 1 1 1
                          3 2        3 1 2        2 2 2 1
                          4 1        3 2 1        3 1 1 1 1
                          5          4 1 1        3 1 1 2
                                     4 2          3 1 2 1
                                     5 1          3 2 1 1
                                     6            3 2 2
                                                  3 3 1
                                                  4 1 1 1
                                                  4 1 2
                                                  4 2 1
                                                  4 3
                                                  5 1 1
                                                  5 2
                                                  6 1
                                                  7.

Cf. A000740, A215474, A228369, A277427.
The binary version is A329318.
The binary non-"co" version is A102659.
A sequence listing all Lyndon compositions is A294859.
Numbers whose binary expansion is co-Lyndon are A328596.
Numbers whose binary expansion is co-Lyndon are A275692.
Binary Lyndon words are A001037.
Lyndon compositions are A059966.
Normal Lyndon words are A060223.
Cf. A211097, A211100, A296372, A296373, A298941, A329131, A329312, A329313, A329314, A329324, A329326.

colynQ[q_]:=Array[Union[{RotateRight[q,#],q}]=={RotateRight[q,#],q}&,Length[q]-1,1,And];
lexsort[f_,c_]:=OrderedQ[PadRight[{f,c}]];
Table[Sort[Select[Join@@Permutations/@IntegerPartitions[n],colynQ],lexsort],{n,5}] (* Gus Wiseman, Nov 15 2019 *)

Row lengths are A059966(n) = number of prime compositions of n.

A296373 Triangle T(n,k) = number of compositions of n whose factorization into Lyndon words (aperiodic necklaces) is of length k.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 6, 5, 3, 1, 1, 9, 12, 6, 3, 1, 1, 18, 21, 14, 6, 3, 1, 1, 30, 45, 27, 15, 6, 3, 1, 1, 56, 84, 61, 29, 15, 6, 3, 1, 1, 99, 170, 120, 67, 30, 15, 6, 3, 1, 1, 186, 323, 254, 136, 69, 30, 15, 6, 3, 1, 1, 335, 640, 510, 295, 142, 70, 30, 15, 6, 3, 1, 1

Offset: 1

Gus Wiseman, Dec 11 2017

			Triangle begins:
    1;
    1,   1;
    2,   1,   1;
    3,   3,   1,   1;
    6,   5,   3,   1,   1;
    9,  12,   6,   3,   1,   1;
   18,  21,  14,   6,   3,   1,   1;
   30,  45,  27,  15,   6,   3,   1,   1;
   56,  84,  61,  29,  15,   6,   3,   1,   1;
   99, 170, 120,  67,  30,  15,   6,   3,   1,   1;
  186, 323, 254, 136,  69,  30,  15,   6,   3,   1,   1;
  335, 640, 510, 295, 142,  70,  30,  15,   6,   3,   1,   1;

Andrew Howroyd, Table of n, a(n) for n = 1..1275
Wikipedia, Lyndon word: Standard factorization

Cf. A000740, A001045, A008965, A019536, A059966, A060223, A185700, A228369, A232472, A277427, A281013, A296302, A296372.

neckQ[q_]:=Array[OrderedQ[{RotateRight[q,#],q}]&,Length[q]-1,1,And];
aperQ[q_]:=UnsameQ@@Table[RotateRight[q,k],{k,Length[q]}];
qit[q_]:=If[#===Length[q],{q},Prepend[qit[Drop[q,#]],Take[q,#]]]&[Max@@Select[Range[Length[q]],neckQ[Take[q,#]]&&aperQ[Take[q,#]]&]];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],Length[qit[#]]===k&]],{n,12},{k,n}]

EulerMT(u)={my(n=#u, p=x*Ser(u), vars=variables(p)); Vec(exp( sum(i=1, n, substvec(p + O(x*x^(n\i)), vars, apply(v->v^i,vars))/i ))-1)}
A(n)=[Vecrev(p/y) | p<-EulerMT(y*vector(n, n, sumdiv(n, d, moebius(n/d) * (2^d-1))/n))]
{ my(T=A(12)); for(n=1, #T, print(T[n])) } \\ Andrew Howroyd, Dec 01 2018

First column is A059966.

cp's OEIS Frontend

A060223 Number of orbits of length n under the map whose periodic points are counted by A000670.

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A296372 Triangle read by rows: T(n,k) is the number of normal sequences of length n whose standard factorization into Lyndon words (aperiodic necklaces) has k factors.

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A281013 Tetrangle T(n,k,i) = i-th part of k-th prime composition of n.

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A296373 Triangle T(n,k) = number of compositions of n whose factorization into Lyndon words (aperiodic necklaces) is of length k.

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Author

Keywords

Examples

Links

Crossrefs

Programs

Mathematica

PARI

Formula