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 1-5 of 5 results.

A131725 Partial sums of A131711.

Original entry on oeis.org

0, 1, 3, 8, 10, 19, 19, 28, 36, 41, 49, 50, 50, 51, 53, 58, 60, 69, 69, 78, 86, 91, 99, 100, 100, 101, 103, 108, 110, 119, 119, 128, 136, 141, 149, 150, 150, 151, 153, 158, 160, 169, 169, 178, 186, 191, 199, 200
Offset: 0

Views

Author

Paul Curtz, Sep 16 2007

Keywords

Crossrefs

Cf. A131711.

Formula

O.g.f.: x*(x^8+8x^7+4x^6+5x^4+4x^2+2x+1)/((x-1)^2*(1+x)*(x^2+x+1)*(x^2-x+1)*(x^4-x^2+1)). - R. J. Mathar, Jul 04 2008
a(n) = a(n-1) + a(n-2) - a(n-3) - a(n-4) + a(n-5) + a(n-6) - a(n-7) - a(n-8) + a(n-9) + a(n-10) - a(n-11) for n > 10. - Chai Wah Wu, Jan 09 2021

Extensions

Edited by R. J. Mathar, Jul 04 2008

A131036 First differences of A131711.

Original entry on oeis.org

1, 1, 3, -3, 7, -9, 9, -1, -3, 3, -7, -1, 1, 1, 3, -3, 7, -9, 9, -1, -3, 3, -7, -1, 1, 1, 3, -3, 7, -9, 9, -1, -3, 3, -7, -1, 1, 1, 3, -3, 7, -9, 9, -1, -3, 3, -7, -1
Offset: 0

Views

Author

Paul Curtz, Sep 23 2007

Keywords

Comments

The equivalent operation on A001333 yields last digits A131707 and their first differences A131715.

Crossrefs

Cf. A131711.

Programs

  • Mathematica
    Differences[PadRight[{},120,{0,1,2,5,2,9,0,9,8,5,8,1}]] (* Harvey P. Dale, Dec 29 2014 *)

Formula

a(n) = a(n-12).
From Chai Wah Wu, Jan 09 2021: (Start)
a(n) = - a(n-1) - a(n-4) - a(n-5) - a(n-8) - a(n-9) for n > 8.
G.f.: (x^8 + 8*x^7 + 4*x^6 + 5*x^4 + 4*x^2 + 2*x + 1)/(x^9 + x^8 + x^5 + x^4 + x + 1). (End)

Extensions

Edited by R. J. Mathar, Jul 07 2008

A131707 Period 12: repeat 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9 .

Original entry on oeis.org

1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7
Offset: 0

Views

Author

Paul Curtz, Sep 14 2007

Keywords

Comments

Also the decimal expansion of 1023949/9000009. [R. J. Mathar, Feb 07 2009]

Crossrefs

Cf. A131711.

Programs

  • Mathematica
    PadRight[{},120,{1,1,3,7,7,1,9,9,7,3,3,9}] (* Harvey P. Dale, May 02 2012 *)

Formula

a(n) = A001333(n) mod 10. - Paul Curtz, Apr 08 2008
G.f.: (1+2x^2+4x^3-6x^5+9x^6)/((1-x)(1+x^2)(1-x^2+x^4)). a(n)=a(n-1)-a(n-6)+a(n-7). [R. J. Mathar, Feb 07 2009]
a(n) = 5-2*cos(Pi*n/6) -2*sin(Pi*n/6)/3 -10*sin(Pi*n/2)/3 -2*cos(5*Pi*n/6) -2*sin(5*Pi*n/6)/3. - R. J. Mathar, Oct 08 2011

Extensions

More terms from Tracy Poff (tracy.poff(AT)gmail.com), Dec 21 2008
Even more periods from R. J. Mathar, Feb 07 2009

A131727 Pell numbers A000129 without last digit.

Original entry on oeis.org

1, 2, 7, 16, 40, 98, 237, 574, 1386, 3346, 8078, 19502, 47083, 113668, 274421, 662510, 1599442, 3861396, 9322235, 22505868, 54333972, 131173812, 316681596, 764537004, 1845755605, 4456048214, 10757852035, 25971752284, 62701356604
Offset: 4

Views

Author

Paul Curtz, Sep 16 2007, Sep 27 2007

Keywords

Programs

Formula

a(n)=(A000129(n)-A131711(n))/10. - R. J. Mathar, Jul 17 2009

Extensions

More terms from R. J. Mathar, Oct 24 2007

A131716 Period 6: repeat [0, 1, 2, 5, 8, 9].

Original entry on oeis.org

0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1, 2, 5, 8, 9, 0, 1
Offset: 0

Views

Author

Paul Curtz, Sep 14 2007

Keywords

Crossrefs

Cf. A131711.

Programs

Formula

From Wesley Ivan Hurt, Jun 19 2016: (Start)
G.f.: x*(1+2*x+5*x^2+8*x^3+9*x^4)/(1-x^6).
a(n) = a(n-6) for n>5.
a(n) = (25 - 5*cos(n*Pi) - 10*cos(n*Pi/3) - 10*cos(2*n*Pi/3) - 14*sqrt(3)*sin(n*Pi/3) - 2*sqrt(3)*sin(2*n*Pi/3))/6. (End)
Showing 1-5 of 5 results.