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.

A369804 Expansion of 1/(1 - x^3/(1-x)^5).

Original entry on oeis.org

1, 0, 0, 1, 5, 15, 36, 80, 181, 431, 1060, 2617, 6401, 15521, 37513, 90741, 219918, 533619, 1295022, 3141826, 7619870, 18478155, 44810670, 108676262, 263576791, 639267800, 1550434777, 3760269946, 9119740067, 22118021213, 53642768716, 130099857234, 315531401964
Offset: 0

Views

Author

Seiichi Manyama, Feb 01 2024

Keywords

Comments

Number of compositions of 5*n-3 into parts 3 and 5.

Crossrefs

Programs

  • PARI
    my(N=40, x='x+O('x^N)); Vec(1/(1-x^3/(1-x)^5))
    
  • PARI
    a(n) = sum(k=0, n\3, binomial(n-1+2*k, n-3*k));

Formula

a(n) = A052920(5*n-3) for n > 0.
a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5) for n > 5.
a(n) = Sum_{k=0..floor(n/3)} binomial(n-1+2*k,n-3*k).
a(n) = A369845(n) - A369845(n-1). - R. J. Mathar, Feb 14 2024

A369845 Number of compositions of 5*n into parts 3 and 5.

Original entry on oeis.org

1, 1, 1, 2, 7, 22, 58, 138, 319, 750, 1810, 4427, 10828, 26349, 63862, 154603, 374521, 908140, 2203162, 5344988, 12964858, 31443013, 76253683, 184929945, 448506736, 1087774536, 2638209313, 6398479259, 15518219326, 37636240539, 91279009255, 221378866489
Offset: 0

Views

Author

Seiichi Manyama, Feb 03 2024

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5, -10, 11, -5, 1}, {1, 1, 1, 2, 7}, 50] (* Paolo Xausa, Mar 15 2024 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(n+2*k, n-3*k));

Formula

a(n) = A052920(5*n).
a(n) = Sum_{k=0..floor(n/3)} binomial(n+2*k,n-3*k).
a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5).
G.f.: (1-x)^4/((1-x)^5 - x^3).
a(n) = A369847(n+1)-A369847(n). - R. J. Mathar, Feb 14 2024

A369846 Number of compositions of 5*n-1 into parts 3 and 5.

Original entry on oeis.org

0, 1, 4, 10, 21, 44, 101, 250, 629, 1557, 3784, 9120, 21992, 53228, 129177, 313701, 761403, 1846804, 4478044, 10858285, 26332515, 63865592, 154900529, 375691009, 911166977, 2209835169, 5359470121, 12998281146, 31524747503, 76457088518, 185431544730
Offset: 1

Views

Author

Seiichi Manyama, Feb 03 2024

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5, -10, 11, -5, 1}, {0, 1, 4, 10, 21}, 50] (* Paolo Xausa, Mar 15 2024 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(n+1+2*k, n-2-3*k));

Formula

a(n) = A052920(5*n-1).
a(n) = Sum_{k=0..floor(n/3)} binomial(n+1+2*k,n-2-3*k).
a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5).
G.f.: x^2*(1-x)/((1-x)^5 - x^3).

A369848 Number of compositions of 5*n-4 into parts 3 and 5.

Original entry on oeis.org

0, 1, 3, 6, 11, 23, 57, 149, 379, 928, 2227, 5336, 12872, 31236, 75949, 184524, 447702, 1085401, 2631240, 6380241, 15474230, 37533077, 91034937, 220790480, 535475968, 1298668192, 3149634952, 7638811025, 18526466357, 44932341015, 108974456212, 264295580664
Offset: 1

Views

Author

Seiichi Manyama, Feb 03 2024

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5, -10, 11, -5, 1}, {0, 1, 3, 6, 11}, 50] (* Paolo Xausa, Mar 15 2024 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(n+2*k, n-2-3*k));

Formula

a(n) = A052920(5*n-4).
a(n) = Sum_{k=0..floor(n/3)} binomial(n+2*k,n-2-3*k).
a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 5*a(n-4) + a(n-5).
G.f.: x^2*(1-x)^2/((1-x)^5 - x^3).
Showing 1-4 of 4 results.