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 1-6 of 6 results.

A369114 Expansion of (1/x) * Series_Reversion( x * ((1-x)^3-x^3) ).

Original entry on oeis.org

1, 3, 15, 92, 630, 4620, 35494, 282015, 2298417, 19108265, 161418543, 1381606044, 11955789440, 104427062460, 919430773992, 8151530382264, 72711166411422, 652075100808960, 5875868463764446, 53175058170610530, 483082193418731280, 4404057834071995110
Offset: 0

Views

Author

Seiichi Manyama, Jan 13 2024

Keywords

Crossrefs

Programs

  • Maple
    A369114 := proc(n)
        add(binomial(n+k,k) * binomial(4*n+2,n-3*k),k=0..floor(n/3)) ;
        %/(n+1) ;
    end proc;
    seq(A369114(n),n=0..70) ; # R. J. Mathar, Jan 25 2024
  • PARI
    my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^3-x^3))/x)
    
  • PARI
    a(n) = sum(k=0, n\3, binomial(n+k, k)*binomial(4*n+2, n-3*k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/3)} binomial(n+k,k) * binomial(4*n+2,n-3*k).
D-finite with recurrence 81*n*(n-1)*(n+1)*a(n) -945*n^2*(n-1)*a(n-1) +441*(n-1)*(3*n^2+9*n-20)*a(n-2) +3*(1039*n^3 -12393*n^2 +37406*n-33232)*a(n-3) -448*(2*n-5) *(4*n-13)*(4*n-11)*a(n-4)=0. - R. J. Mathar, Jan 25 2024

A369124 Expansion of (1/x) * Series_Reversion( x * ((1-x)^4+x^4) ).

Original entry on oeis.org

1, 4, 26, 204, 1770, 16352, 157696, 1569096, 15988652, 165998624, 1749696208, 18673883696, 201394693864, 2191421381632, 24028822589440, 265238416143584, 2944999336948944, 32869042668479424, 368551132961138784, 4149643380825661824, 46897527236429235520
Offset: 0

Views

Author

Seiichi Manyama, Jan 13 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^4+x^4))/x)
    
  • PARI
    a(n) = sum(k=0, n\4, (-1)^k*binomial(n+k, k)*binomial(5*n+3, n-4*k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+k,k) * binomial(5*n+3,n-4*k).

A369161 Expansion of (1/x) * Series_Reversion( x * ((1-x)^3-x^4) ).

Original entry on oeis.org

1, 3, 15, 91, 613, 4410, 33190, 258129, 2058281, 16737259, 138268611, 1157197639, 9790774861, 83606543660, 719638883748, 6237175439640, 54386540912490, 476782443732437, 4199713449255749, 37151346765537606, 329914740292813170, 2939975733035070000
Offset: 0

Views

Author

Seiichi Manyama, Jan 15 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^3-x^4))/x)
    
  • PARI
    a(n) = sum(k=0, n\4, binomial(n+k, k)*binomial(4*n-k+2, n-4*k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} binomial(n+k,k) * binomial(4*n-k+2,n-4*k).

A369160 Expansion of (1/x) * Series_Reversion( x * ((1-x)^2-x^4) ).

Original entry on oeis.org

1, 2, 7, 30, 144, 742, 4012, 22458, 129035, 756602, 4509141, 27233726, 166320987, 1025356360, 6372494608, 39882831334, 251146002084, 1590079213920, 10115878798130, 64634124182670, 414578955678690, 2668578654593970, 17232252926468640, 111602332042716450
Offset: 0

Views

Author

Seiichi Manyama, Jan 15 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^2-x^4))/x)
    
  • PARI
    a(n) = sum(k=0, n\4, binomial(n+k, k)*binomial(3*n-2*k+1, n-4*k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} binomial(n+k,k) * binomial(3*n-2*k+1,n-4*k).

A368011 Expansion of (1/x) * Series_Reversion( x * ((1-x)^5-x^5) ).

Original entry on oeis.org

1, 5, 40, 385, 4095, 46377, 548380, 6691620, 83637450, 1065311665, 13777916774, 180451354720, 2388503030675, 31900445734050, 429369814375480, 5818270533841408, 79309912829992350, 1086768622818959100, 14961519902879613700, 206839961042385226110
Offset: 0

Views

Author

Seiichi Manyama, Jan 13 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^5-x^5))/x)
    
  • PARI
    a(n) = sum(k=0, n\5, binomial(n+k, k)*binomial(6*n+4, n-5*k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/5)} binomial(n+k,k) * binomial(6*n+4,n-5*k).

A369216 Expansion of (1/x) * Series_Reversion( x * ((1-x)^4-x) ).

Original entry on oeis.org

1, 5, 44, 479, 5827, 75887, 1034980, 14593794, 211031650, 3112385177, 46636714566, 707983562624, 10865572966703, 168306274609798, 2627854427929448, 41314461126179272, 653481096161664690, 10391753978329136808, 166040704868503173384
Offset: 0

Views

Author

Seiichi Manyama, Jan 16 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serreverse(x*((1-x)^4-x))/x)
    
  • PARI
    a(n) = sum(k=0, n, binomial(n+k, k)*binomial(5*n+3*k+3, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(n+k,k) * binomial(5*n+3*k+3,n-k).
Showing 1-6 of 6 results.