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.

A382537 Expansion of 1/(1 - x*(1 + 4*x)^(5/2)).

Original entry on oeis.org

1, 1, 11, 51, 211, 1061, 4923, 22765, 107687, 502479, 2352231, 11022911, 51590795, 241559783, 1131156175, 5295875131, 24797055115, 116104311885, 543622665219, 2545347081565, 11917847333151, 55801588711565, 261274518155435, 1223337818786305, 5727913381451455
Offset: 0

Views

Author

Seiichi Manyama, Mar 31 2025

Keywords

Crossrefs

Programs

  • Magma
    R := PowerSeriesRing(Rationals(), 40); f := 1/(1 - x*(1 + 4*x)^(5/2)); seq := [ Coefficient(f, n) : n in [0..30] ];seq; // Vincenzo Librandi, Apr 02 2025
  • Mathematica
    Table[Sum[4^(n-k)*Binomial[5*k/2,n-k],{k,0,n}],{n,0,25}] (* Vincenzo Librandi, Apr 02 2025 *)
  • PARI
    a(n) = sum(k=0, n, 4^(n-k)*binomial(5*k/2, n-k));
    

Formula

a(n) = Sum_{k=0..n} 4^(n-k) * binomial(5*k/2,n-k).

A382538 Expansion of 1/(1 - x*(1 + 4*x)^(7/2)).

Original entry on oeis.org

1, 1, 15, 99, 519, 3165, 19503, 115053, 688803, 4141863, 24778355, 148376447, 889216143, 5326274463, 31903872267, 191123789739, 1144894457103, 6858232252437, 41083285178247, 246102886383661, 1474237118571467, 8831178384769525, 52901735792001759
Offset: 0

Views

Author

Seiichi Manyama, Mar 31 2025

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 28); Coefficients(R!( 1/(1 - x*(1 + 4*x)^(7/2)))); // Vincenzo Librandi, May 16 2025
  • Mathematica
    Table[Sum[4^(n-k)* Binomial[7*k/2, n-k],{k,0,n}],{n,0,28}] (* Vincenzo Librandi, May 16 2025 *)
  • PARI
    a(n) = sum(k=0, n, 4^(n-k)*binomial(7*k/2, n-k));
    

Formula

a(n) = Sum_{k=0..n} 4^(n-k) * binomial(7*k/2,n-k).
D-finite with recurrence (-n+1)*a(n) +2*(-2*n+11)*a(n-1) +(n-1)*a(n-2) +2*(16*n-25)*a(n-3) +56*(8*n-17)*a(n-4) +224*(16*n-43)*a(n-5) +4480*(4*n-13)*a(n-6) +3584*(16*n-61)*a(n-7) +14336*(8*n-35)*a(n-8) +8192*(16*n-79)*a(n-9) +32768*(2*n-11)*a(n-10)=0. - R. J. Mathar, Apr 02 2025

A382649 Expansion of 1/(1 - x*(1 + 4*x)^(3/2))^2.

Original entry on oeis.org

1, 2, 15, 52, 213, 834, 3043, 11576, 41601, 152458, 544039, 1950132, 6895773, 24403302, 85542339, 300101048, 1044436937, 3639851814, 12594713911, 43660404108, 150357976533, 518991977194, 1780132570723, 6122965091976, 20928650616113, 71779065646510, 244590689773839
Offset: 0

Views

Author

Seiichi Manyama, Apr 02 2025

Keywords

Comments

a(82) is negative.

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 28); Coefficients(R!( 1/(1 - x*(1 + 4*x)^(3/2))^2)); // Vincenzo Librandi, May 13 2025
  • Mathematica
    Table[Sum[4^(n-k)* (k+1)* Binomial[3*k/2, n-k],{k,0,n}],{n,0,28}] (* Vincenzo Librandi, May 13 2025 *)
  • PARI
    a(n) = sum(k=0, n, 4^(n-k)*(k+1)*binomial(3*k/2, n-k));
    

Formula

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

A382650 Expansion of 1/(1 - x*(1 + 4*x)^(3/2))^3.

Original entry on oeis.org

1, 3, 24, 100, 471, 2043, 8422, 34818, 137649, 543655, 2096508, 8031948, 30355155, 113929497, 423562614, 1565841650, 5745557853, 20989365057, 76206968356, 275721399480, 992423144247, 3562075121911, 12728422443654, 45379998032202, 161158522838105, 571293893581389
Offset: 0

Views

Author

Seiichi Manyama, Apr 02 2025

Keywords

Comments

a(100) is negative.

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, 4^(n-k)*binomial(k+2, 2)*binomial(3*k/2, n-k));

Formula

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