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.

Showing 1-7 of 7 results.

A132191 Square array a(m,n) read by antidiagonals, defined by A000010(n)*a(m,n) = Sum_{k=1..n, gcd(k,n)=1} m^{ Sum_{d|n} A000010(d)/ (multiplicative order of k modulo d) }.

Original entry on oeis.org

1, 1, 2, 1, 4, 3, 1, 6, 9, 4, 1, 12, 18, 16, 5, 1, 12, 54, 40, 25, 6, 1, 40, 72, 160, 75, 36, 7, 1, 28, 405, 280, 375, 126, 49, 8, 1, 96, 390, 2176, 825, 756, 196, 64, 9, 1, 104, 1944, 2800, 8125, 2016, 1372, 288, 81, 10, 1, 280, 3411, 17920, 13175, 23976, 4312, 2304, 405
Offset: 1

Views

Author

N. J. A. Sloane, Dec 01 2007, based on email from Max Alekseyev, Nov 08 2007

Keywords

Comments

From Andrew Howroyd, Apr 22 2017: (Start)
Number of step shifted (decimated) sequences of length n using a maximum of m different symbols. See A056371 for an explanation of step shifts. -
Number of mappings with domain {0..n-1} and codomain {1..m} up to equivalence. Mappings A and B are equivalent if there is a d, prime to n, such that A(i) = B(i*d mod n) for i in {0..n-1}. (End)

Examples

			Array begins:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
2, 4, 6, 12, 12, 40, 28, 96, 104, 280, 216, 1248, 704, 2800, 4344, 8928, 8232, 44224, 29204, 136032, ...
3, 9, 18, 54, 72, 405, 390, 1944, 3411, 14985, 17802, 139968, 133104, 798525, 1804518, 5454378, 8072532, 64599849, 64573626, 437732424, ...
4, 16, 40, 160, 280, 2176, 2800, 17920, 44224, 263296, 419872, 4280320, 5594000, 44751616, 134391040, 539054080, 1073758360, 11453771776, 15271054960, 137575813120, ...
5, 25, 75, 375, 825, 8125, 13175, 103125, 327125, 2445625, 4884435, 61640625, 101732425, 1017323125, 3816215625, 19104609375, 47683838325, 635787765625, 1059638680675, 11924780390625, ...
		

Crossrefs

Row m=2 is A056371
Row m=3 is A056372
Row m=4 is A056373
Row m=5 is A056374
Row m=6 is A056375
Column n=2 is A000290
Column n=3 is A002411
Column n=4 is A019582

Programs

  • 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[m-n+1, n], {m, 1, 15}, {n, m, 1, -1}] // Flatten (* Jean-François Alcover, Dec 01 2015 *)
  • PARI
    for(i=1,15,for(m=1,i,n=i-m+1; print1(sum(k=1, n, if(gcd(k,n)==1, m^sumdiv(n,d,eulerphi(d)/znorder(Mod(k,d))),0))/eulerphi(n)","))) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 26 2008

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 26 2008
Offset corrected by Andrew Howroyd, Apr 20 2017

A056372 Number of step shifted (decimated) sequences using a maximum of three different symbols.

Original entry on oeis.org

3, 9, 18, 54, 72, 405, 390, 1944, 3411, 14985, 17802, 139968, 133104, 798525, 1804518, 5454378, 8072532, 64599849, 64573626, 437732424, 872157294, 3138159429, 4279259574, 35362084140, 42364514403, 211822562025, 423646166250
Offset: 1

Views

Author

Keywords

Comments

See A056371 for an explanation of step shifts.

Crossrefs

Cf. A056411.
A row or column of A132191.

Programs

  • 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[3, n], {n, 1, 27}] (* Jean-François Alcover, Dec 04 2015 *)

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

Extensions

More terms from Max Alekseyev, Nov 08 2007

A056373 Number of step shifted (decimated) sequences using a maximum of four different symbols.

Original entry on oeis.org

4, 16, 40, 160, 280, 2176, 2800, 17920, 44224, 263296, 419872, 4280320, 5594000, 44751616, 134391040, 539054080, 1073758360, 11453771776, 15271054960, 137575813120, 366528038400, 1759220283904, 3198580043440, 35193817661440, 56294998751872
Offset: 1

Views

Author

Keywords

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]

Crossrefs

Cf. A056412.
A row or column of A132191.

Programs

  • 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[4, n], {n, 1, 25}] (* Jean-François Alcover, Dec 04 2015 *)

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

Extensions

More terms from Max Alekseyev, Nov 08 2007

A056374 Number of step shifted (decimated) sequences using a maximum of five different symbols.

Original entry on oeis.org

5, 25, 75, 375, 825, 8125, 13175, 103125, 327125, 2445625, 4884435, 61640625, 101732425, 1017323125, 3816215625, 19104609375, 47683838325, 635787765625, 1059638680675, 11924780390625, 39736963221875, 238418603522125, 541860418146375
Offset: 1

Views

Author

Keywords

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]

Crossrefs

Cf. A056413.
A row or column of A132191.

Programs

  • 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[5, n], {n, 1, 23}] (* Jean-François Alcover, Dec 04 2015 *)

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

Extensions

More terms from Max Alekseyev, Nov 08 2007

A056395 Number of step shifted (decimated) sequence structures using a maximum of six different symbols.

Original entry on oeis.org

1, 2, 4, 11, 18, 117, 161, 1193, 3530, 27569, 60333, 863409, 1636609, 19122031, 84580125, 501915567, 1492170609, 23751685183, 47340359591, 637742820401, 2546703019245, 18317620839483, 49923584451715
Offset: 1

Views

Author

Keywords

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]

Crossrefs

Cf. A056375.

Formula

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

A056380 Number of step shifted (decimated) sequences using exactly six different symbols.

Original entry on oeis.org

0, 0, 0, 0, 0, 360, 2520, 48060, 317520, 4109040, 12923136, 238785300, 559279980, 7612396920, 37864711260, 246263046840, 787758864480, 13282478342640, 27723264985920, 387585098313300, 1595144664456720
Offset: 1

Views

Author

Keywords

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]

Crossrefs

Cf. A056375.

Formula

A056375(n)-6*A056374(n)+15*A056373(n)-20*A056372(n)+15*A056371(n)-6.

A056385 Number of primitive (aperiodic) step shifted (decimated) sequences using a maximum of six different symbols.

Original entry on oeis.org

6, 30, 120, 720, 2010, 23820, 46950, 434700, 1683450, 15126810, 36284466, 547180200, 1088416050, 13060942950, 58782162480, 352913410080, 1057916846190, 16926687985950, 33853322280030
Offset: 1

Views

Author

Keywords

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]

Formula

sum mu(d)*A056375(n/d) where d|n.
Showing 1-7 of 7 results.