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.

A372005 G.f. A(x) satisfies A(x) = ( 1 + 16*x*A(x)*(1 + x*A(x)) )^(1/4).

Original entry on oeis.org

1, 4, -4, 0, 136, -1152, 5152, 0, -230560, 2267136, -11355008, 0, 594412800, -6184304640, 32458736640, 0, -1828185954816, 19583341166592, -105435193825280, 0, 6195266435870720, -67554137604096000, 369569533686562816, 0, -22322916873246359552, 246346071588005216256
Offset: 0

Views

Author

Seiichi Manyama, Apr 15 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, 16^k*binomial(n/4+1/4, k)*binomial(k, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} 16^k * binomial(n/4+1/4,k) * binomial(k,n-k).
a(4*n+3) = 0 for n >= 0.
a(n) = 16^n*binomial((n+1)/4, n)*hypergeom([(1-n)/2, -n/2], [(5-3*n)/4], 1/4)/(n+1). - Stefano Spezia, Apr 18 2024

A372019 G.f. A(x) satisfies A(x) = ( 1 + 9*x*A(x)/(1 - x*A(x)) )^(1/3).

Original entry on oeis.org

1, 3, 3, 3, 30, 57, 84, 867, 1893, 3162, 33132, 76953, 136812, 1446204, 3478764, 6420387, 68260134, 167946159, 317782524, 3392340186, 8479140510, 16332164868, 174873206424, 442212416121, 863222622780, 9264327739716, 23637757714788, 46624054987452
Offset: 0

Views

Author

Seiichi Manyama, Apr 15 2024

Keywords

Crossrefs

Programs

  • Maple
    A371019 := proc(n)
        add(9^k*binomial((n+1)/3,k)*binomial(n-1,k-1),k=0..n) ;
        %/(n+1) ;
    end proc:
    seq(A371019(n),n=0..60) ; # R. J. Mathar, Apr 22 2024
  • PARI
    a(n) = sum(k=0, n, 9^k*binomial(n/3+1/3, k)*binomial(n-1, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} 9^k * binomial(n/3+1/3,k) * binomial(n-1,n-k).
D-finite with recurrence n*(n-1)*(n+1)*a(n) -8*(2*n-5)*(8*n^2-40*n+57)*a(n-3) +4096*(n-5)*(n-6)*(n-4)*a(n-6)=0. - R. J. Mathar, Apr 22 2024

A372006 G.f. A(x) satisfies A(x) = ( 1 + 25*x*A(x)*(1 + x*A(x)) )^(1/5).

Original entry on oeis.org

1, 5, -20, 100, 0, -9625, 169875, -1933125, 14025625, 0, -2065744375, 41575056250, -523670743750, 4119815531250, 0, -684944792812500, 14442398472421875, -189324209836328125, 1541918426557031250, 0, -271410262779871875000, 5860693797318871093750
Offset: 0

Views

Author

Seiichi Manyama, Apr 15 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, 25^k*binomial(n/5+1/5, k)*binomial(k, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} 25^k * binomial(n/5+1/5,k) * binomial(k,n-k).
a(5*n+4) = 0 for n >= 0.
a(n) = 25^n*binomial((n+1)/5, n)*hypergeom([(1-n)/2, -n/2], [(6-4*n)/5], 4/25)/(n+1). - Stefano Spezia, Apr 18 2024

A372091 G.f. A(x) satisfies A(x) = 1/( 1 - 9*x*A(x)*(1 + x*A(x)) )^(1/3).

Original entry on oeis.org

1, 3, 30, 378, 5382, 82377, 1323153, 21998493, 375346062, 6534966438, 115634273139, 2073448947960, 37593341804520, 688026597386004, 12694000438662381, 235845671565830850, 4408763725976408766, 82861865131590443808, 1564885072909535335695
Offset: 0

Views

Author

Seiichi Manyama, Apr 17 2024

Keywords

Crossrefs

Cf. A372004.

Programs

  • PARI
    a(n) = sum(k=0, n, 9^k*binomial(n/3+k-2/3, k)*binomial(k, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} 9^k * binomial(n/3+k-2/3,k) * binomial(k,n-k).
a(n) = 9^n*binomial((4*n-2)/3, n)*hypergeom([(1-n)/2, -n/2], [(2-4*n)/3], -4/9)/(n+1). - Stefano Spezia, Apr 18 2024
Showing 1-4 of 4 results.