cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A032165 Number of aperiodic necklaces of n beads of 10 colors.

Original entry on oeis.org

10, 45, 330, 2475, 19998, 166485, 1428570, 12498750, 111111000, 999989991, 9090909090, 83333249175, 769230769230, 7142856428565, 66666666659934, 624999993750000, 5882352941176470, 55555555499944500
Offset: 1

Views

Author

Keywords

Crossrefs

Column 10 of A074650.

Programs

  • Mathematica
    f[d_]:=MoebiusMu[d] 10^(n/d)/n; a[n_]:=Total[f/@Divisors[n]]; a[0]=1; Table[a[n], {n, 1, 20}] (* Vincenzo Librandi, Oct 14 2017 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(d)*10^(n/d))/n; \\ Andrew Howroyd, Oct 13 2017

Formula

"CHK" (necklace, identity, unlabeled) transform of 10, 0, 0, 0...
a(n) = Sum_{d|n} mu(d)*10^(n/d)/n.
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 10*x^k))/k. - Ilya Gutkovskiy, May 19 2019

A032166 Number of aperiodic necklaces of n beads of 11 colors.

Original entry on oeis.org

11, 55, 440, 3630, 32208, 295020, 2783880, 26793030, 261994040, 2593726344, 25937424600, 261535549220, 2655593241840, 27124986721140, 278483211283552, 2871858103075830, 29732178147017280
Offset: 1

Views

Author

Keywords

Comments

Number of monic irreducible polynomials of degree n over GF(11). # Robert Israel, Jan 07 2015

Crossrefs

Column 11 of A074650.

Programs

  • Maple
    f:= (n,p) -> add(numtheory:-mobius(d)*p^(n/d),d=numtheory:-divisors(n))/n:
    seq(f(n,11), n=1..100); # Robert Israel, Jan 07 2015
  • Mathematica
    f[d_]:=MoebiusMu[d] 11^(n/d)/n; a[n_]:=Total[f/@Divisors[n]]; a[0]=1; Table[a[n], {n, 1, 30}] (* Vincenzo Librandi, Oct 14 2017 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(d)*11^(n/d))/n; \\ Michel Marcus, Jan 07 2015

Formula

"CHK" (necklace, identity, unlabeled) transform of 11, 0, 0, 0...
a(n) = Sum_{d|n} mu(d)*11^(n/d)/n.
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 11*x^k))/k. - Ilya Gutkovskiy, May 19 2019

A032167 Number of aperiodic necklaces of n beads of 12 colors.

Original entry on oeis.org

12, 66, 572, 5148, 49764, 497354, 5118828, 53745120, 573308736, 6191711526, 67546215516, 743008120140, 8230246567620, 91708459194066, 1027134771622388, 11555266154065920, 130506535690613940
Offset: 1

Views

Author

Keywords

Crossrefs

Column 12 of A074650.

Programs

  • Mathematica
    f[d_]:=MoebiusMu[d] 12^(n/d)/n; a[n_]:=Total[f/@Divisors[n]]; a[0]=1; Table[a[n], {n, 1, 30}] (* Vincenzo Librandi, Oct 14 2017 *)

Formula

"CHK" (necklace, identity, unlabeled) transform of 12, 0, 0, 0...
a(n) = Sum_{d|n} mu(d)*12^(n/d)/n.
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 12*x^k))/k. - Ilya Gutkovskiy, May 19 2019

A320075 Number of length n primitive (=aperiodic or period n) 10-ary words which are earlier in lexicographic order than any other word derived by cyclic shifts of the alphabet.

Original entry on oeis.org

1, 9, 99, 990, 9999, 99891, 999999, 9999000, 99999900, 999989991, 9999999999, 99999899010, 999999999999, 9999998999991, 99999999989901, 999999990000000, 9999999999999999, 99999999899900100, 999999999999999999, 9999999998999999010, 99999999999998999901
Offset: 1

Views

Author

Alois P. Heinz, Oct 05 2018

Keywords

Comments

Dirichlet convolution of mu(n) with 10^(n-1).

Crossrefs

Column k=10 of A143325.
First differences of A320094.

Programs

  • Maple
    a:= n-> add(`if`(d=n, 10^(n-1), -a(d)), d=numtheory[divisors](n)):
    seq(a(n), n=1..25);

Formula

a(n) = Sum_{d|n} 10^(d-1) * mu(n/d).
a(n) = 10^(n-1) - Sum_{d
a(n) = A143325(n,10).
a(n) = A074650(n,10) * n/10.
a(n) = A143324(n,10) / 10.
G.f.: Sum_{k>=1} mu(k)*x^k/(1 - 10*x^k). - Ilya Gutkovskiy, Oct 25 2018

A383011 Square array A(n,k), n >= 1, k >= 1, read by antidiagonals downwards, where A(n,k) = -(1/n) * Sum_{d|n} mu(n/d) * (-k)^d.

Original entry on oeis.org

1, 2, -1, 3, -3, 0, 4, -6, 2, 0, 5, -10, 8, -3, 0, 6, -15, 20, -18, 6, 0, 7, -21, 40, -60, 48, -11, 0, 8, -28, 70, -150, 204, -124, 18, 0, 9, -36, 112, -315, 624, -690, 312, -30, 0, 10, -45, 168, -588, 1554, -2620, 2340, -810, 56, 0, 11, -55, 240, -1008, 3360, -7805, 11160, -8160, 2184, -105, 0
Offset: 1

Author

Seiichi Manyama, Apr 12 2025

Keywords

Examples

			Square array begins:
   1,   2,    3,    4,     5,     6,      7, ...
  -1,  -3,   -6,  -10,   -15,   -21,    -28, ...
   0,   2,    8,   20,    40,    70,    112, ...
   0,  -3,  -18,  -60,  -150,  -315,   -588, ...
   0,   6,   48,  204,   624,  1554,   3360, ...
   0, -11, -124, -690, -2620, -7805, -19656, ...
   0,  18,  312, 2340, 11160, 39990, 117648, ...
		

Crossrefs

Columns k=1..5 give A154955, A038063, A038064, A038065, A038066.
Main diagonal gives A383012.

Programs

  • PARI
    a(n, k) = -sumdiv(n, d, moebius(n/d)*(-k)^d)/n;

Formula

G.f. of column k: Sum_{j>=1} mu(j) * log(1 + k*x^j) / j.
Product_{n>=1} 1/(1 - x^n)^A(n,k) = 1 + k*x.

A060216 Number of orbits of length n under the full 13-shift (whose periodic points are counted by A001022).

Original entry on oeis.org

13, 78, 728, 7098, 74256, 804076, 8964072, 101962770, 1178277464, 13785812040, 162923672184, 1941506688940, 23298085122480, 281241165925044, 3412392867581152, 41588538022965570
Offset: 1

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of monic irreducible polynomials of degree n over GF(13). - Robert Israel, Jan 07 2015
Number of Lyndon words (aperiodic necklaces) with n beads of 13 colors. - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=78 since there are 169 points of period 2 in the full 13-shift and 13 fixed points, so there must be (169-13)/2 = 78 orbits of length 2.
		

Crossrefs

Column 13 of A074650.
Cf. A001022.

Programs

  • Maple
    f:= n -> add(numtheory:-mobius(d)*13^(n/d),d=numtheory:-divisors(n))/n;
    seq(f(n), n=1..100); # Robert Israel, Jan 07 2015
  • Mathematica
    a[n_]:=(1/n) * Sum[MoebiusMu[d] *13^(n/d), {d, Divisors[n]}]; Table[a[n], {n, 20}] (* Indranil Ghosh, Mar 26 2017 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(d)*13^(n/d))/n; \\ Michel Marcus, Jan 07 2015
    
  • Python
    from sympy import divisors, mobius
    print([sum(mobius(d) * 13**(n//d) for d in divisors(n))//n for n in range(1, 21)]) # Indranil Ghosh, Mar 26 2017

Formula

a(n) = (1/n)* Sum_{d|n} mu(d) 13^(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 13*x^k))/k. - Ilya Gutkovskiy, May 19 2019

A060217 Number of orbits of length n under the full 14-shift (whose periodic points are counted by A001023).

Original entry on oeis.org

14, 91, 910, 9555, 107562, 1254435, 15059070, 184468830, 2295671560, 28925411697, 368142288150, 4724492067295, 61054982558010, 793714765724595, 10371206370484778, 136122083520848880, 1793608631137129170, 23715491899442676060, 314542313628890231430, 4183412771249777343369
Offset: 1

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of Lyndon words (aperiodic necklaces) with n beads of 14 colors. - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=91 since there are 196 points of period 2 in the full 14-shift and 14 fixed points, so there must be (196-14)/2 = 91 orbits of length 2.
		

Crossrefs

Column 14 of A074650.
Cf. A001023.

Programs

  • Magma
    A060217:= func< n | (&+[MoebiusMu(d)*14^Floor(n/d): d in Divisors(n)])/n >;
    [A060217(n): n in [1..40]]; // G. C. Greubel, Aug 01 2024
    
  • Mathematica
    A060217[n_]:= DivisorSum[n, MoebiusMu[#]*14^(n/#) &]/n;
    Table[A060217[n], {n,40}] (* G. C. Greubel, Aug 01 2024 *)
  • PARI
    a001023(n) = 14^n;
    a(n) = (1/n)*sumdiv(n, d, moebius(d)*a001023(n/d)); \\ Michel Marcus, Sep 11 2017
    
  • SageMath
    def A060217(n): return sum(moebius(k)*14^(n//k) for k in (1..n) if (k).divides(n))/n
    [A060217(n) for n in range(1,41)] # G. C. Greubel, Aug 01 2024

Formula

a(n) = (1/n)* Sum_{d|n} mu(d)*A001023(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 14*x^k))/k. - Ilya Gutkovskiy, May 19 2019

Extensions

More terms from Michel Marcus, Sep 11 2017

A060218 Number of orbits of length n under the full 15-shift (whose periodic points are counted by A001024).

Original entry on oeis.org

15, 105, 1120, 12600, 151872, 1897840, 24408480, 320355000, 4271484000, 57664963104, 786341441760, 10812193870800, 149707312950720, 2085208989609360, 29192926025339776, 410525522071875000, 5795654431511374080, 82105104444274758000, 1166756747396368729440, 16626283650369421872480
Offset: 1

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of Lyndon words (aperiodic necklaces) with n beads of 15 colors. - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=105 since there are 225 points of period 2 in the full 15-shift and 15 fixed points, so there must be (225-15)/2 = 105 orbits of length 2.
		

Crossrefs

Column 15 of A074650.
Cf. A001024.

Programs

  • Magma
    A060218:= func< n | (&+[MoebiusMu(d)*15^Floor(n/d): d in Divisors(n)])/n >;
    [A060218(n): n in [1..40]]; // G. C. Greubel, Aug 01 2024
    
  • Maple
    f:= n -> 1/n*add(numtheory:-mobius(d)*15^(n/d), d = numtheory:-divisors(n)):
    map(f, [$1..30]); # Robert Israel, Oct 28 2018
  • Mathematica
    A060218[n_]:= DivisorSum[n, MoebiusMu[#]*15^(n/#) &]/n;
    Table[A060218[n], {n, 40}] (* G. C. Greubel, Aug 01 2024 *)
  • PARI
    a001024(n) = 15^n;
    a(n) = (1/n)*sumdiv(n, d, moebius(d)*a001024(n/d)); \\ Michel Marcus, Sep 11 2017
    
  • SageMath
    def A060218(n): return sum(moebius(k)*15^(n//k) for k in (1..n) if (k).divides(n))/n
    [A060218(n) for n in range(1,41)] # G. C. Greubel, Aug 01 2024

Formula

a(n) = (1/n)* Sum_{d|n} mu(d)*A001024(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 15*x^k))/k. - Ilya Gutkovskiy, May 19 2019

Extensions

More terms from Michel Marcus, Sep 11 2017

A060219 Number of orbits of length n under the full 16-shift (whose periodic points are counted by A001025).

Original entry on oeis.org

16, 120, 1360, 16320, 209712, 2795480, 38347920, 536862720, 7635496960, 109951057896, 1599289640400, 23456246655680, 346430740566960, 5146970983535160, 76861433640386288, 1152921504338411520, 17361641481138401520, 262353693488939386880, 3976729669784964390480
Offset: 1

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of monic irreducible polynomials of degree n over GF(16). - Robert Israel, Jan 07 2015
Number of Lyndon words (aperiodic necklaces) with n beads of 16 colors. - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=120 since there are 256 points of period 2 in the full 16-shift and 16 fixed points, so there must be (256-16)/2 = 120 orbits of length 2.
		

Crossrefs

Column 16 of A074650.
Cf. A001025.

Programs

  • Magma
    A060219:= func< n | (&+[MoebiusMu(d)*16^Floor(n/d): d in Divisors(n)])/n >;
    [A060219(n): n in [1..40]]; // G. C. Greubel, Aug 01 2024
    
  • Maple
    f:= (n,p) -> add(numtheory:-mobius(d)*p^(n/d),d=numtheory:-divisors(n))/n:
    seq(f(n,16),n=1..30); # Robert Israel, Jan 07 2015
  • Mathematica
    A060219[n_]:= DivisorSum[n, MoebiusMu[#]*16^(n/#) &]/n;Table[A060219[n], {n, 40}] (* G. C. Greubel, Aug 01 2024 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(d)*16^(n/d))/n; \\ Michel Marcus, Jan 07 2015
    
  • SageMath
    def A060219(n): return sum(moebius(k)*16^(n//k) for k in (1..n) if (k).divides(n))/n
    [A060219(n) for n in range(1, 41)] # G. C. Greubel, Aug 01 2024

Formula

a(n) = (1/n)* Sum_{d|n} mu(d)*16^(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 16*x^k))/k. - Ilya Gutkovskiy, May 19 2019

Extensions

Terms a(17) onward added by G. C. Greubel, Aug 01 2024

A060220 Number of orbits of length n under the full 17-shift (whose periodic points are counted by A001026).

Original entry on oeis.org

17, 136, 1632, 20808, 283968, 4022064, 58619808, 871959240, 13176430176, 201599248032, 3115626937056, 48551851084080, 761890617915840, 12026987582075856, 190828203433892736, 3041324491793194440, 48661191875666868480, 781282469552728498992, 12582759772902701307744
Offset: 1

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of monic irreducible polynomials of degree n over GF(17). - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=136 since there are 289 points of period 2 in the full 17-shift and 17 fixed points, so there must be (289-17)/2 = 136 orbits of length 2.
		

Crossrefs

Column 17 of A074650.

Programs

  • Magma
    A060220:= func< n | (1/n)*(&+[MoebiusMu(d)*(17)^Floor(n/d): d in Divisors(n)]) >;
    [A060220(n): n in [1..40]]; // G. C. Greubel, Sep 13 2024
    
  • Mathematica
    A060220[n_]:= DivisorSum[n, (17)^(n/#)*MoebiusMu[#] &]/n;
    Table[A060220[n], {n,40}] (* G. C. Greubel, Sep 13 2024 *)
  • PARI
    a001024(n) = 17^n;
    a(n) = (1/n)*sumdiv(n, d, moebius(d)*a001024(n/d)); \\ Michel Marcus, Sep 11 2017
    
  • SageMath
    def A060220(n): return (1/n)*sum(moebius(k)*(17)^(n/k) for k in (1..n) if (k).divides(n))
    [A060220(n) for n in range(1,41)] # G. C. Greubel, Sep 13 2024

Formula

a(n) = (1/n)* Sum_{d|n} mu(d)*A001026(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 17*x^k))/k. - Ilya Gutkovskiy, May 20 2019

Extensions

More terms from Michel Marcus, Sep 11 2017
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