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 1-4 of 4 results.

A137531 a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3).

Original entry on oeis.org

1, 4, 10, 23, 53, 123, 286, 665, 1546, 3594, 8355, 19423, 45153, 104968, 244021, 567280, 1318766, 3065759, 7127025, 16568323, 38516678, 89540413, 208156206, 483904470, 1124941411, 2615171499, 6079536145, 14133206848, 32855719753, 76380281708, 177562612466
Offset: 0

Views

Author

Paul Curtz, Apr 25 2008

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{3, -2, 1}, {1, 4, 10}, 100] (* G. C. Greubel, Feb 17 2017 *)
  • PARI
    a=[1,4,10];for(i=1,99,a=concat(a,3*a[#a]-2*a[#a-1]+a[#a-2]));a \\ Charles R Greathouse IV, Jun 01 2011
    
  • PARI
    Vec((1 + x) / (1 - 3*x + 2*x^2 - x^3) + O(x^40)) \\ Colin Barker, Feb 17 2017

Formula

G.f.: (1 + x) / (1 - 3*x + 2*x^2 - x^3). - Colin Barker, Feb 17 2017

Extensions

More terms from Vladimir Joseph Stephan Orlovsky, Jan 20 2009

A159348 Transform of the finite sequence (1, 0, -1, 0, 1) by the T_{0,0} transform (see link).

Original entry on oeis.org

1, 1, 1, 4, 11, 24, 55, 128, 298, 693, 1611, 3745, 8706, 20239, 47050, 109378, 254273, 591113, 1374171, 3194560, 7426451, 17264404, 40134870, 93302253, 216901423, 504234633, 1172203306, 2725042075, 6334954246, 14726981894, 34236079265
Offset: 0

Views

Author

Richard Choulet, Apr 11 2009

Keywords

Crossrefs

Programs

  • Magma
    I:=[11,24,55]; [1,1,1,4] cat [n le 3 select I[n] else 3*Self(n-1) - 2*Self(n-2) +Self(n-3): n in [1..30]]; // G. C. Greubel, Jun 16 2018
  • Maple
    a(0):=1: a(1):=1:a(2):=1: a(3):=4:a(4):=11:a(5):=24:a(6):=55:for n from 4 to 31 do a(n+3):=3*a(n+2)-2*a(n+1)+a(n):od:seq(a(i),i=0..31);
  • Mathematica
    Join[{1,1,1,4},LinearRecurrence[{3,-2,1},{11,24,55},40]] (* or *) CoefficientList[Series[(-1+2 x-2 x^3+2 x^5-x^6)/(-1+3 x-2 x^2+x^3),{x,0,45}],x](* Harvey P. Dale, Oct 04 2011 *)
  • PARI
    m=50; v=concat([11, 24, 55], vector(m-3)); for(n=4, m, v[n]= 3*v[n-1] -2*v[n-2] +v[n-3]); concat([1,1,1,4], v) \\ G. C. Greubel, Jun 16 2018
    

Formula

O.g.f.: f(z) = ((1-z)^2/(1-3*z+2*z^2-z^3))*(1-z^2+z^4).
a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) for n>=7, with a(0)=1, a(1)=1, a(2)=1, a(3)=4, a(4)=11, a(5)=24, a(6)=55.

A159349 Transform of the finite sequence (1, 0, -1, 0, 1, 0, -1) by the T_{0,0} transformation (see link).

Original entry on oeis.org

1, 1, 1, 4, 11, 24, 56, 129, 300, 698, 1623, 3773, 8771, 20390, 47401, 110194, 256170, 595523, 1384423, 3218393, 7481856, 17393205, 40434296, 93998334, 218519615, 507996473, 1180948523, 2745372238, 6382216141, 14836852470, 34491497366
Offset: 0

Views

Author

Richard Choulet, Apr 11 2009

Keywords

Crossrefs

Programs

  • Magma
    I:=[56, 129, 300]; [1,1,1,4,11,24] cat [n le 3 select I[n] else 3*Self(n-1) - 2*Self(n-2) +Self(n-3): n in [1..50]]; // G. C. Greubel, Jun 16 2018
  • Maple
    a(0):=1: a(1):=1:a(2):=1: a(3):=4:a(4):=11:a(5):=24:a(6):=56:a(7):=129:a(8):=300:for n from 6 to 31 do a(n+3):=3*a(n+2)-2*a(n+1)+a(n):od:seq(a(i),i=0..31);
  • Mathematica
    Join[{1, 1, 1, 4, 11, 24}, LinearRecurrence[{3, -2, 1}, {56, 129, 300}, 95]] (* G. C. Greubel, Jun 16 2018 *)
  • PARI
    m=50; v=concat([56,129,300], vector(m-3)); for(n=4, m, v[n]= 3*v[n-1] -2*v[n-2] +v[n-3]); concat([1,1,1,4,11,24], v) \\ G. C. Greubel, Jun 16 2018
    

Formula

O.g.f.: (1-2x+2x^3-2x^5+2x^6-2x^7+x^8)/(1-3x+2x^2-x^3). [corrected by Georg Fischer, May 19 2019]
a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) for n>=9, with a(0)=1, a(1)=1, a(2)=1, a(3)=4, a(4)=11, a(5)=24, a(6)=56, a(7)=129, a(8)=300.

A159350 Transform of A056594 by the T_{0,0} transformation (see link).

Original entry on oeis.org

1, 1, 1, 4, 11, 24, 54, 127, 297, 689, 1600, 3721, 8652, 20112, 46753, 108689, 252673, 587392, 1365519, 3174448, 7379698, 17155715, 39882197, 92714861, 215535904, 501060185, 1164823608, 2707886360, 6295072049, 14634267033, 34020543361
Offset: 0

Views

Author

Richard Choulet, Apr 11 2009

Keywords

Crossrefs

Programs

  • Magma
    I:=[1,1,1,4,11]; [n le 5 select I[n] else 3*Self(n-1) - 3*Self(n-2) +4*Self(n-3) -2*Self(n-4) + Self(n-5): n in [1..50]]; // G. C. Greubel, Jun 15 2018
  • Maple
    a(0):=1: a(1):=1: a(2):=1: a(3):=4: a(4):=11: for n from 0 to 31 do a(n+5):=3*a(n+4)-3*a(n+3)+4*a(n+2)-2*a(n+1)+a(n): od: seq(a(i),i=0..31);
  • Mathematica
    LinearRecurrence[{3,-3,4,-2,1}, {1,1,1,4,11}, 50] (* G. C. Greubel, Jun 15 2018 *)
  • PARI
    x='x+O('x^50); Vec((1-x)^2/((1-3*x+2*x^2-x^3)*(1+x^2))) \\ G. C. Greubel, Jun 15 2018
    

Formula

O.g.f.: (1-z)^2/((1-3*z+2*z^2-z^3)*(1+z^2)).
a(n) = 3*a(n-1) - 3*a(n-2) + 4*a(n-3) - 2*a(n-4) + a(n-5) for n >= 5, with a(0)=1, a(1)=1, a(2)=1, a(3)=4, a(4)=11.
Showing 1-4 of 4 results.