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 1-6 of 6 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

A056393 Number of step shifted (decimated) sequence structures using a maximum of four different symbols.

Original entry on oeis.org

1, 2, 4, 11, 17, 107, 131, 811, 1893, 11107, 17599, 179371, 233449, 1866057, 5603787, 22469291, 44744047, 477262537, 636308685, 5732457131, 15272176697, 73301054891, 133274359129, 1466413263531
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

Formula

Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.
a(n) = Sum_{k=1..4} A288620(n, k). - Andrew Howroyd, Jun 13 2017

A056378 Number of step shifted (decimated) sequences using exactly four different symbols.

Original entry on oeis.org

0, 0, 0, 12, 60, 792, 1404, 10716, 31200, 205032, 349956, 3727932, 5065804, 41574312, 127199028, 517290132, 1041517620, 11195637720, 15012935676, 135825699612, 363040469732, 1746670165416, 3181465294092
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. A056373.

Formula

A056373(n)-4*A056372(n)+6*A056371(n)-4.

A056379 Number of step shifted (decimated) sequences using exactly five different symbols.

Original entry on oeis.org

0, 0, 0, 0, 30, 900, 2800, 32010, 139080, 1276200, 2960940, 41626230, 75086430, 801522300, 3162262170, 16463793480, 42395689530, 579164463000, 983928850100, 11241277288950, 37913042835300
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. A056374.

Formula

A056374(n)-5*A056373(n)+10*A056372(n)-10*A056371(n)+5.

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.

A056383 Number of primitive (aperiodic) step shifted (decimated) sequences using a maximum of four different symbols.

Original entry on oeis.org

4, 12, 36, 144, 276, 2124, 2796, 17760, 44184, 263004, 419868, 4278000, 5593996, 44748804, 134390724, 539036160, 1073758356, 11453725416, 15271054956, 137575549680, 366528035564, 1759219864020, 3198580043436
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

Formula

a(n) = Sum_{d|n} mu(d)*A056373(n/d).
Showing 1-6 of 6 results.