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.

Previous Showing 11-15 of 15 results.

A366595 G.f. A(x) satisfies A(x) = 1 + x^4*(1+x)^3*A(x)^4.

Original entry on oeis.org

1, 0, 0, 0, 1, 3, 3, 1, 4, 24, 60, 80, 82, 222, 796, 1848, 2912, 4452, 11088, 31592, 70467, 125437, 231105, 551775, 1399069, 3068219, 5942937, 12017739, 27966515, 66675777, 145719483, 298344501, 632955999, 1449806573, 3346606719, 7335193353, 15557399668
Offset: 0

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Author

Seiichi Manyama, Oct 14 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n\4, binomial(3*k, n-4*k)*binomial(4*k, k)/(3*k+1));

Formula

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

A367641 G.f. A(x) satisfies A(x) = (1 + x)^2 + x*A(x)^4 / (1 + x)^3.

Original entry on oeis.org

1, 3, 10, 64, 504, 4368, 40208, 385728, 3813888, 38590208, 397648384, 4158436864, 44020882944, 470804670464, 5079479547904, 55217003536384, 604200374845440, 6649658071007232, 73560096496779264, 817467602640830464, 9121818467786162176
Offset: 0

Views

Author

Seiichi Manyama, Nov 25 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(3*k+2, n-k)*binomial(4*k, k)/(3*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(3*k+2,n-k) * binomial(4*k,k)/(3*k+1).
D-finite with recurrence 3*n*(5589*n-14914)*(3*n-1)*(3*n+1)*a(n) +(150903*n^4 -5939762*n^3 +21653157*n^2 -22049842*n +6856944)*a(n-1) +6*(-2312427*n^4 +15333754*n^3 -28367401*n^2 +6040114*n +14892656)*a(n-2) +24*(-3942141*n^4 +46541449*n^3 -199851671*n^2 +367766019*n -243569600)*a(n-3) -32*(n-5)*(8043984*n^3 -85808428*n^2 +305023231*n -361082892)*a(n-4) -384*(n-5)*(n-6)*(885234*n^2 -6808468*n +12951185)*a(n-5) -1536*(n-6)*(n-7)*(144699*n^2 -1203919*n +2337211)*a(n-6) -2048*(n-6)*(n-7)*(n-8)*(27819*n-74186)*a(n-7)=0. - R. J. Mathar, Dec 04 2023

A366593 G.f. A(x) satisfies A(x) = 1 + x^2*(1+x)^3*A(x)^4.

Original entry on oeis.org

1, 0, 1, 3, 7, 25, 82, 278, 992, 3552, 12985, 48107, 179977, 680079, 2589915, 9931573, 38319117, 148640195, 579349123, 2267818509, 8911575579, 35141656433, 139018921717, 551557089103, 2194155973751, 8750097458849, 34973989188202, 140085055366350
Offset: 0

Views

Author

Seiichi Manyama, Oct 14 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n\2, binomial(3*k, n-2*k)*binomial(4*k, k)/(3*k+1));

Formula

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

A378786 G.f. A(x) satisfies A(x) = 1 + x * (1+x)^2 * A(x)^4.

Original entry on oeis.org

1, 1, 6, 39, 296, 2435, 21138, 190603, 1767968, 16761424, 161697576, 1582171216, 15664531716, 156637712953, 1579664567130, 16048129755157, 164085811289360, 1687224436103842, 17436287104620980, 181001686332329224, 1886522317836670988, 19734386503541838083
Offset: 0

Views

Author

Seiichi Manyama, Dec 07 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n, r=1, s=2, t=4, u=0) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+r));

Formula

a(n) = Sum_{k=0..n} binomial(4*k+1,k) * binomial(2*k,n-k)/(4*k+1) = Sum_{k=0..n} binomial(2*k,n-k) * A002293(k).

A382892 G.f. A(x) satisfies A(x) = 1/( 1 - x * (1+x)^3 * A(x) )^3.

Original entry on oeis.org

1, 3, 24, 190, 1659, 15309, 146986, 1453536, 14704917, 151479031, 1583533308, 16756882194, 179149227231, 1932144798513, 20996553430206, 229678298803028, 2527034248221849, 27947027713469307, 310494250880357488, 3463870813896354726, 38787008808135775299
Offset: 0

Views

Author

Seiichi Manyama, Apr 08 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n, r=3, s=3, t=4, u=0) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+r));

Formula

G.f. A(x) satisfies A(x) = ( 1 + x * (1+x)^3 * A(x)^(4/3) )^3.
If g.f. satisfies A(x) = ( 1 + x*A(x)^(t/r) * (1 + x*A(x)^(u/r))^s )^r, then a(n) = r * Sum_{k=0..n} binomial(t*k+u*(n-k)+r,k) * binomial(s*k,n-k)/(t*k+u*(n-k)+r).
G.f.: B(x)^3, where B(x) is the g.f. of A366272.
Previous Showing 11-15 of 15 results.