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 1-10 of 17 results. Next

A261406 Numbers n such that the norm of Phi_n(alpha), the n-th cyclotomic polynomial evaluated at alpha, is +-1, where alpha is the Salem number defined in A073011.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 13, 16, 17, 18, 20, 21, 23, 24, 27, 28, 29, 30, 34, 37, 38, 40, 42, 44, 45, 47, 50, 52, 56, 57, 60, 63, 65, 66, 70, 74, 75, 76, 78, 84, 86, 92, 96, 98, 105, 110, 118, 132, 138, 144, 154, 160, 165, 186, 195, 204, 212, 240, 270, 286, 360
Offset: 1

Views

Author

N. J. A. Sloane, Aug 22 2015

Keywords

References

  • Cohen, Henri, Leonard Lewin, and Don Zagier. "A sixteenth-order polylogarithm ladder." Experimental Mathematics 1.1 (1992): 25-34.

Crossrefs

Cf. A073011.

A261407 Numbers d_m arising in Cohen et al.'s investigation of "ladder relations" among powers of the Salem number A073011.

Original entry on oeis.org

1, 2, 1, 24, 1, 81, 1, 63057, 1, 234280024, 1
Offset: 2

Views

Author

N. J. A. Sloane, Aug 22 2015

Keywords

Comments

See Cohen et al. (1992) for precise definition.

References

  • Cohen, Henri, Leonard Lewin, and Don Zagier. "A sixteenth-order polylogarithm ladder." Experimental Mathematics 1.1 (1992): 25-34. See Table 1.

Crossrefs

Cf. A073011.

A029826 Expansion of 1/(x^10+x^9-x^7-x^6-x^5-x^4-x^3+x+1) (inverse of Salem polynomial).

Original entry on oeis.org

1, -1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 2, 1, 2, 3, 2, 4, 3, 5, 5, 6, 8, 8, 10, 12, 14, 16, 20, 22, 27, 31, 37, 44, 50, 61, 70, 83, 98, 115, 135, 159, 187, 220, 259, 304, 359, 420, 496, 583, 685, 807, 948, 1116, 1312, 1544
Offset: 0

Views

Author

Keywords

Comments

The root 1.1762808182599175065440703384740350... is the smallest known Salem number (A073011).

Crossrefs

Programs

  • Magma
    m:=50; R:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(x^10+x^9-x^7-x^6-x^5-x^4-x^3+x+1))); // G. C. Greubel, May 07 2018
  • Mathematica
    LinearRecurrence[{-1,0,1,1,1,1,1,0,-1,-1}, {1,-1,1,0,0,1,0,1,0,1}, 100] (* G. C. Greubel, May 07 2018 *)
  • PARI
    Vec(1/(x^10+x^9-x^7-x^6-x^5-x^4-x^3+x+1)+O(x^66)) \\ Joerg Arndt, May 01 2018
    

Formula

a(n) = -a(n-1) + a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7) - a(n-9) - a(n-10). - Roger L. Bagula and Gary W. Adamson, Oct 23 2008

A181600 Expansion of 1/(1 - x - x^2 + x^8 - x^10).

Original entry on oeis.org

1, 1, 2, 3, 5, 8, 13, 21, 33, 53, 85, 136, 218, 349, 559, 895, 1434, 2297, 3679, 5893, 9439, 15119, 24217, 38790, 62132, 99520, 159407, 255331, 408978, 655083, 1049283, 1680695, 2692063, 4312028, 6906816, 11063033, 17720278, 28383559, 45463532, 72821479
Offset: 0

Views

Author

Roger L. Bagula, May 06 2013

Keywords

Comments

Limiting ratio is 1.60176..., the largest real root of -1 + x^2 - x^8 - x^9 + x^10. Compare this constant to Lehmer's Salem constant A073011 and the golden mean.

Crossrefs

Programs

  • Magma
    m:=50; R:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1 -x-x^2+x^8-x^10))); // G. C. Greubel, Nov 03 2018
  • Mathematica
    CoefficientList[Series[1/(1 - x - x^2 + x^8 - x^10), {x, 0, 50}], x]
    LinearRecurrence[{1, 1, 0, 0, 0, 0, 0, -1, 0, 1}, {1, 1, 2, 3, 5, 8, 13, 21, 33, 53}, 50] (* Harvey P. Dale, Aug 11 2015 *)
  • PARI
    Vec(1/(1 -x -x^2 +x^8 -x^10) + O(x^50)) \\ G. C. Greubel, Nov 16 2016
    

Formula

a(n) = a(n-1) + a(n-2) - a(n-8) + a(n-10). - Franck Maminirina Ramaharo, Oct 31 2018

A219300 Decimal expansion of the second smallest known Salem number.

Original entry on oeis.org

1, 1, 8, 8, 3, 6, 8, 1, 4, 7, 5, 0, 8, 2, 2, 3, 5, 8, 8, 1, 4, 2, 9, 6, 0, 9, 5, 8, 6, 2, 9, 5, 9, 3, 5, 9, 4, 7, 0, 4, 7, 0, 4, 5, 6, 0, 0, 6, 2, 9, 0, 5, 6, 8, 8, 7, 4, 1, 4, 5, 3, 3, 7, 1, 2, 9, 1, 9, 6, 0, 6, 4, 1, 4, 0, 2, 1, 7, 4, 5, 8, 9, 4, 7, 5, 8, 3, 5, 0, 9, 8, 8, 0, 6, 7, 9, 6, 7, 7, 4, 5, 0, 8, 8, 8
Offset: 1

Views

Author

Arkadiusz Wesolowski, Nov 17 2012

Keywords

Comments

This number is algebraic of degree 18. Sequence A073011 contains the smallest known Salem number.
It is the only root r of the polynomial x^18 - x^17 + x^16 - x^15 - x^12 + x^11 - x^10 + x^9 - x^8 + x^7 - x^6 - x^3 + x^2 - x + 1 with abs(r) > 1. - Joerg Arndt, Nov 18 2012

Examples

			1.188368147508223588142960958....
		

Crossrefs

Programs

  • Mathematica
    RealDigits[x /. FindRoot[x^18 - x^17 + x^16 - x^15 - x^12 + x^11 - x^10 + x^9 - x^8 + x^7 - x^6 - x^3 + x^2 - x + 1 == 0, {x, 1, 2}, WorkingPrecision -> 200]][[1]]

A306078 Decimal expansion of the third smallest known Salem number.

Original entry on oeis.org

1, 2, 0, 0, 0, 2, 6, 5, 2, 3, 9, 8, 7, 3, 9, 1, 5, 1, 8, 9, 0, 2, 9, 6, 2, 1, 0, 0, 4, 1, 4, 6, 0, 1, 5, 6, 7, 2, 4, 0, 6, 1, 8, 1, 5, 1, 9, 9, 9, 8, 5, 1, 0, 6, 7, 9, 2, 4, 3, 9, 9, 8, 3, 9, 8, 8, 6, 0, 7, 3, 1, 1, 3, 4, 4, 2, 5, 2, 4, 0, 9, 6, 4, 4, 2, 4, 6, 1, 7, 2, 7, 8, 8, 4, 9, 6, 9, 9, 1, 0
Offset: 1

Views

Author

Jean-François Alcover, Jun 19 2018

Keywords

Examples

			1.200026523987391518902962100414601567240618151999851067924399839886...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306079 (sigma4).

Programs

  • Mathematica
    c1 = {1, 0, 0, -1, -1, 0, 0, 1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2]-1]). c2;
    sigma3 = Root[p, x, 2];
    RealDigits[sigma3, 10, 100][[1]]
  • PARI
    polrootsreal(x^14 - x^11 - x^10 + x^7 - x^4 - x^3 + 1)[2] \\ Charles R Greathouse IV, Feb 11 2025

A306079 Decimal expansion of the fourth smallest known Salem number.

Original entry on oeis.org

1, 2, 0, 2, 6, 1, 6, 7, 4, 3, 6, 8, 8, 6, 0, 4, 2, 6, 1, 1, 1, 8, 2, 9, 5, 4, 1, 5, 9, 4, 8, 6, 1, 9, 0, 4, 5, 3, 4, 3, 9, 4, 9, 8, 3, 4, 9, 6, 9, 5, 2, 3, 0, 4, 3, 6, 8, 5, 3, 0, 9, 5, 7, 6, 7, 2, 6, 4, 5, 4, 0, 6, 5, 8, 7, 6, 3, 6, 5, 5, 5, 3, 7, 7, 2, 6, 7, 1, 0, 8, 0, 0, 5, 5, 1, 8, 2, 6, 5, 7, 6, 7
Offset: 1

Views

Author

Jean-François Alcover, Jun 19 2018

Keywords

Examples

			1.20261674368860426111829541594861904534394983496952304368530957672645...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3).

Programs

  • Mathematica
    c1 = {1, 0, -1, 0, 0, 0, 0, -1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2]-1]).c2;
    sigma4 = Root[p, x, 2];
    RealDigits[sigma4, 10, 102][[1]]
  • PARI
    polrootsreal(x^14 - x^12 - x^7 - x^2 + 1)[2] \\ Charles R Greathouse IV, Feb 11 2025

A316605 Decimal expansion of the fifth smallest known Salem number.

Original entry on oeis.org

1, 2, 1, 6, 3, 9, 1, 6, 6, 1, 1, 3, 8, 2, 6, 5, 0, 9, 1, 6, 2, 6, 8, 0, 6, 3, 1, 1, 1, 9, 9, 4, 6, 3, 3, 2, 7, 7, 2, 2, 2, 5, 3, 6, 0, 6, 5, 7, 0, 5, 7, 0, 7, 5, 7, 5, 6, 0, 4, 2, 7, 0, 6, 5, 8, 3, 8, 3, 1, 2, 1, 2, 9, 4, 6, 1, 8, 4, 9, 5, 9, 4, 4, 2, 6, 3, 7, 9, 6, 6, 6, 7, 0, 9, 5, 4, 3, 9, 5, 4, 2, 8
Offset: 1

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.21639166113826509162680631119946332772225360657057075756042706583831...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3), A306079 (sigma4), A316606 (sigma6), A316607 (sigma7), A316608 (sigma8), A316609 (sigma9), A316610 (sigma10).

Programs

  • Mathematica
    c1 = {1, 0, 0, 0, -1, -1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma5 = Root[p, x, 2];
    RealDigits[sigma5, 10, 102][[1]]
  • PARI
    polrootsreal(1 - x^4 - x^5 - x^6 + x^10)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

p = 1 - x^4 - x^5 - x^6 + x^10.

A316606 Decimal expansion of the sixth smallest known Salem number.

Original entry on oeis.org

1, 2, 1, 9, 7, 2, 0, 8, 5, 9, 0, 4, 0, 3, 1, 1, 8, 4, 4, 1, 6, 9, 6, 0, 6, 7, 6, 0, 4, 1, 4, 6, 7, 7, 9, 4, 4, 3, 9, 0, 4, 1, 5, 5, 0, 5, 5, 4, 1, 5, 6, 9, 6, 7, 8, 2, 8, 7, 9, 7, 4, 4, 1, 7, 8, 7, 3, 3, 8, 4, 6, 4, 5, 9, 9, 0, 8, 3, 9, 0, 6, 5, 8, 3, 5, 5, 3, 9, 3, 2, 0, 7, 8, 5, 1, 6, 2, 5, 9, 5, 7, 8
Offset: 1

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.219720859040311844169606760414677944390415505541569678287974417873...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3 ), A306079 (sigma4), A316605 (sigma5), A316607 (sigma7), A316608 (sigma8), A316609 (sigma9), A316610 (sigma10).

Programs

  • Mathematica
    c1 = {1, -1, 0, 0, 0, 0, 0, 0, -1, 1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma6 = Root[p, x, 2];
    RealDigits[sigma6, 10, 102][[1]]
  • PARI
    polrootsreal(1 - x - x^8 + x^9 - x^10 - x^17 + x^18)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

Equals root of p = 1 - x - x^8 + x^9 - x^10 - x^17 + x^18 with largest absolute value.

A316607 Decimal expansion of the seventh smallest known Salem number.

Original entry on oeis.org

1, 2, 3, 0, 3, 9, 1, 4, 3, 4, 4, 0, 7, 2, 2, 4, 7, 0, 2, 7, 9, 0, 1, 7, 7, 9, 3, 8, 9, 7, 5, 2, 7, 9, 0, 1, 7, 5, 6, 6, 5, 7, 4, 4, 8, 9, 6, 6, 1, 7, 5, 6, 2, 4, 1, 4, 0, 1, 9, 1, 4, 2, 3, 6, 1, 7, 2, 8, 1, 3, 4, 4, 7, 8, 5, 3, 5, 4, 5, 4, 1, 6, 7, 3, 5, 9, 8, 4, 6, 5, 1, 6, 6, 2, 4, 0, 8, 5, 2, 8, 5, 6
Offset: 1

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.2303914344072247027901779389752790175665744896617562414019142361728...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3 ), A306079 (sigma4), A316605 (sigma5), A316606 (sigma6), A316608 (sigma8), A316609 (sigma9), A316610 (sigma10).

Programs

  • Mathematica
    c1 = {1, 0, 0, -1, 0, -1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma7 = Root[p, x, 2];
    RealDigits[sigma7, 10, 102][[1]]
  • PARI
    polrootsreal(1 - x^3 - x^5 - x^7 + x^10)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

p = 1 - x^3 - x^5 - x^7 + x^10.
Showing 1-10 of 17 results. Next