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.

Previous Showing 11-17 of 17 results.

A316608 Decimal expansion of the eighth smallest known Salem number.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.2326135485931210039627316948079097914115773712098310467299165820538...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3 ), A306079 (sigma4), A316605 (sigma5), A316606 (sigma6), A316607 (sigma7), A316609 (sigma9), A316610 (sigma10).

Programs

  • Mathematica
    c1 = {1, -1, 0, 0, 0, -1, 1, 0, 0, -1, 1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma8 = Root[p, x, 2];
    RealDigits[sigma8, 10, 102][[1]]
  • PARI
    polrootsreal(1 - x - x^5 + x^6 - x^9 + x^10 - x^11 + x^14 - x^15 - x^19 + x^20)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

p = 1 - x - x^5 + x^6 - x^9 + x^10 - x^11 + x^14 - x^15 - x^19 + x^20.

A316609 Decimal expansion of the ninth smallest known Salem number.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.2356645803897473081051693515312634797235100427462390776504380772063...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3 ), A306079 (sigma4), A316605 (sigma5), A316606 (sigma6), A316607 (sigma7), A316608 (sigma8), A316610 (sigma10).

Programs

  • Mathematica
    c1 = {1, 0, -1, -1, 0, 0, 0, 1, 1, 0, -1, -1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma9 = Root[p, x, 2];
    RealDigits[sigma9, 10, 101][[1]]
  • PARI
    polrootsreal(1 - x^2 - x^3 + x^7 + x^8 - x^10 - x^11 - x^12 + x^14 + x^15 - x^19 - x^20 + x^22)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

p = 1 - x^2 - x^3 + x^7 + x^8 - x^10 - x^11 - x^12 + x^14 + x^15 - x^19 - x^20 + x^22.

A316610 Decimal expansion of the tenth smallest known Salem number.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 08 2018

Keywords

Examples

			1.2363179318032304898990948698020545539448192083678695637947537841118...
		

Crossrefs

Cf. A073011 (sigma1), A219300 (sigma2), A306078 (sigma3 ), A306079 (sigma4), A316605 (sigma5), A316606 (sigma6), A316607 (sigma7), A316608 (sigma8), A316609 (sigma9).

Programs

  • Mathematica
    c1 = {1, -1, 0, 0, 0, 0, 0, 0, -1};
    c2 = Join[c1, Reverse[Most[c1]]];
    p = (x^Range[0, Length[c2] - 1]).c2;
    sigma10 = Root[p, x, 2];
    RealDigits[sigma10, 10, 102][[1]]
  • PARI
    polrootsreal(1 - x - x^8 - x^15 + x^16)[2] \\ Charles R Greathouse IV, Feb 11 2025

Formula

p = 1 - x - x^8 - x^15 + x^16.

A070178 Coefficients of Lehmer's polynomial.

Original entry on oeis.org

1, 1, 0, -1, -1, -1, -1, -1, 0, 1, 1
Offset: 0

Views

Author

N. J. A. Sloane, May 13 2002

Keywords

Comments

Mahler's measure M(f) of a polynomial f is defined to be the absolute value of the product of those roots of f which lie outside the unit disk, multiplied by the absolute value of the coefficient of the leading term of f. Of all polynomials with integer coefficients, Lehmer's 10th degree polynomial produces the smallest known M(f), given in A073011. - Hugo Pfoertner, Mar 12 2006

Examples

			Polynomial is 1+x-x^3-x^4-x^5-x^6-x^7+x^9+x^10.
		

References

  • H. L. Montgomery, Ten Lectures on the Interface Between Analytic Number Theory and Harmonic Analysis, Amer. Math. Soc., 1996, p. 205.

Crossrefs

Cf. A073011 (Mahler's measure of Lehmer's polynomial).

A167289 Signature sequence of the smallest Salem number of degree 18 (A219300).

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 4, 3, 2, 1, 5, 4, 3, 2, 1, 6, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3, 2, 8, 1, 7, 6, 5, 4, 3, 9, 2, 8, 1, 7, 6, 5, 4, 10, 3, 9, 2, 8, 1, 7, 6, 5, 11, 4, 10, 3, 9, 2, 8, 1, 7, 6, 12, 5, 11, 4, 10, 3, 9, 2, 8, 1, 7, 13, 6, 12, 5, 11, 4, 10, 3, 9, 2, 8, 14, 1, 7, 13, 6, 12, 5, 11, 4, 10, 3, 9, 15
Offset: 1

Views

Author

Roger L. Bagula, Nov 01 2009

Keywords

Crossrefs

Programs

  • Mathematica
    a = {1, -1, 1, -1, 0, 0, -1, 1, -1};
    b = Join[a, {1}, Reverse[a]];
    p[x_] = Sum[b[[n]]*x^(n - 1), {n, 1, Length[b]}];
    m = Root[p[x], 2];
    Take[Transpose[Sort[Flatten[Table[{i + j*m, i}, {i, 25}, {j, 17}], 1], #1[[1]] < #2[[1]] &]][[2]], 95]

A142155 Expansion of x/( 1+x-x^2-x^4-x^5-x^6-x^7+x^9+x^10 ).

Original entry on oeis.org

1, -1, 2, -3, 6, -9, 17, -27, 48, -80, 139, -233, 402, -680, 1165, -1979, 3382, -5754, 9822, -16727, 28531, -48613, 82893, -141268, 240847, -410505, 699808, -1192838, 2033410, -3466085, 5908459, -10071512, 17168221, -29265017, 49885842, -85035890, 144953845, -247090156, 421194210
Offset: 1

Views

Author

Roger L. Bagula and Gary W. Adamson, Sep 15 2008

Keywords

Comments

limit_{n->infinity} a(n+1)/a(n) = -1.70461...

Crossrefs

Cf. A073011.

Programs

  • Mathematica
    Rest[CoefficientList[Series[x/(1+x-x^2-x^4-x^5-x^6-x^7+x^9+x^10),{x,0,50}],x]]  (* Harvey P. Dale, Mar 03 2011 *)
  • PARI
    x='x+O('x^50); Vec(x/(1+x-x^2-x^4-x^5-x^6-x^7+x^9+x^10)) \\ G. C. Greubel, Mar 05 2017

Formula

Generating function g(x) = x/( 1+x-x^2-x^4-x^5-x^6-x^7+x^9+x^10 ) = 1/(x^10* p(1/x)) with p(x)= 1 +x -x^3 -x^4 -x^5 -x^6 -x^8 +x^9 +x^10.

Extensions

Definition simplified by the Assoc. Eds. of the OEIS, Jun 30 2010

A177738 a(n) = floor( (x^n - x^(-n)) / (x - x^(-1)) ) where x = Pi-2.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 15, 17, 20, 23, 26, 30, 35, 40, 46, 52, 60, 69, 78, 90, 103, 117, 134, 153, 175, 199, 228, 260, 297, 339, 387, 442, 505, 576, 658, 751, 858, 979, 1118, 1277, 1457, 1664, 1900, 2169, 2476, 2826
Offset: 0

Views

Author

Roger L. Bagula, May 12 2010

Keywords

Comments

The ratio a(n+1)/a(n) approaches Pi-2 as n approaches infinity, and is lower than even Salem polynomial expansions based on A073011.
The idea is the emulation of quadratic beta integer domains using a transcendental number base with a ratio below A073011.

Crossrefs

Programs

  • Mathematica
    Clear[a, n, b]; b = Pi - 2; a[n_] = (b^n - b^(-n))/(b - b^(-1));
    Table[Floor[a[n]], {n, 0, 50}]

Extensions

Undefined terminology removed from the definition - The Assoc. Eds. of the OEIS, May 14 2010
Previous Showing 11-17 of 17 results.