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 1-3 of 3 results.

A134977 Period 6: repeat [1, 4, 2, 3, 0, 2].

Original entry on oeis.org

1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2, 1, 4, 2, 3, 0, 2
Offset: 0

Views

Author

Paul Curtz, Feb 04 2008

Keywords

Comments

Northwest diagonal sums of A134658, omitting row 0.

Crossrefs

Programs

Formula

O.g.f.: -1/(x+1)-2/(x-1)+x/(x^2-x+1). a(n) = 2-(-1)^n+A010892(n-1). - R. J. Mathar, Feb 08 2008
From Wesley Ivan Hurt, Jun 18 2016: (Start)
a(n) = a(n-1) - a(n-3) + a(n-4) for n>3.
a(n) = (6-3*cos(n*Pi)+2*sqrt(3)*sin(n*Pi/3))/3. (End)

A134987 Third extended Jacobsthal recurrence: a(n)=4a(n-1)-6(n-2)+4a(n-3)-a(n-4)+2a(n-5).

Original entry on oeis.org

0, 0, 0, 0, 1, 4, 10, 20, 35, 58, 100, 192, 405, 880, 1874, 3844, 7631, 14886, 29020, 57192, 114249, 230300, 465226, 936948, 1877771, 3748498, 7470532, 14895728, 29749837, 59514152, 119166962, 238627620, 477606935, 955315390, 1909991772, 3818208792
Offset: 0

Views

Author

Paul Curtz, Feb 05 2008

Keywords

Comments

See A134658. Sequence is identical to half its fourth differences from second term.

Programs

  • Mathematica
    LinearRecurrence[{4,-6,4,-1,2},{0,0,0,0,1},60] (* Harvey P. Dale, Jul 12 2011 *)

Formula

O.g.f.: -1/[9(2x-1)]+(-4x^3-2x^2-1)/[9(x^4+2x^2-2x+1)]. - R. J. Mathar, Feb 06 2008

Extensions

More terms from Harvey P. Dale, Jul 12 2011

A135541 a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3), with a(0) = 2, a(1) = 2.

Original entry on oeis.org

0, 2, 7, 12, 21, 44, 91, 180, 357, 716, 1435, 2868, 5733, 11468, 22939, 45876, 91749, 183500, 367003, 734004, 1468005, 2936012, 5872027, 11744052, 23488101, 46976204, 93952411, 187904820, 375809637, 751619276, 1503238555, 3006477108
Offset: 0

Views

Author

Paul Curtz, Feb 22 2008

Keywords

Crossrefs

Programs

  • Magma
    I:=[0, 2, 7]; [n le 3 select I[n] else 2*Self(n-1)-Self(n-2)+2*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jun 17 2012
  • Mathematica
    LinearRecurrence[{2,-1,2},{0,2,7},40] (* Vincenzo Librandi, Jun 17 2012 *)

Formula

From R. J. Mathar, Feb 23 2008: (Start)
O.g.f.: -7/(5*(2x-1)) - (4x+7)/(5*(x^2+1)).
a(n) = (7*2^n - (-1)^floor(n/2)*A010712(n+1))/5. (End)
E.g.f.: (1/5)*(7*cosh(2*x) + 7*sinh(2*x) - 7*cos(x) - 4*sin(x)). - G. C. Greubel, Oct 18 2016

Extensions

More terms from R. J. Mathar, Feb 23 2008
Showing 1-3 of 3 results.