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.

A364742 G.f. satisfies A(x) = 1 / (1 - x*(1 + x*A(x))^3).

Original entry on oeis.org

1, 1, 4, 13, 50, 201, 841, 3627, 15993, 71803, 327082, 1508002, 7023446, 32995626, 156173668, 744029238, 3565030063, 17169013899, 83061503584, 403483653745, 1967217524551, 9623463731721, 47220968518786, 232354408276613, 1146254897566224, 5668118931395946
Offset: 0

Views

Author

Seiichi Manyama, Aug 05 2023

Keywords

Crossrefs

Programs

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

Formula

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

A371612 G.f. satisfies A(x) = ( 1 + x / (1 - x*A(x)^2) )^2.

Original entry on oeis.org

1, 2, 3, 12, 49, 218, 1037, 5106, 25909, 134410, 709691, 3801498, 20606654, 112828202, 623087675, 3466539248, 19411070496, 109313442562, 618713495451, 3517737628368, 20081523836403, 115058714898196, 661432784830204, 3813891082337178, 22052422636145522
Offset: 0

Views

Author

Seiichi Manyama, Mar 29 2024

Keywords

Crossrefs

Programs

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

Formula

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

A364744 G.f. satisfies A(x) = 1 / (1 - x*(1 + x*A(x))^5).

Original entry on oeis.org

1, 1, 6, 26, 131, 706, 3932, 22618, 133099, 797545, 4850296, 29859028, 185712831, 1165227025, 7366475715, 46877977451, 300049605259, 1930395961235, 12476394685445, 80968876247330, 527424073700966, 3447190219684125, 22599794010813360
Offset: 0

Views

Author

Seiichi Manyama, Aug 05 2023

Keywords

Crossrefs

Programs

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

Formula

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

A364762 G.f. satisfies A(x) = 1 / (1 + x*(1 + x*A(x))^4).

Original entry on oeis.org

1, -1, -3, 5, 29, -42, -349, 384, 4705, -3307, -67530, 19392, 1006479, 140594, -15356600, -8897336, 237691865, 246737931, -3708348277, -5655844305, 58027927950, 119178376245, -906834380800, -2396063640645, 14094956420555, 46748815762429, -216921227330074
Offset: 0

Views

Author

Seiichi Manyama, Aug 05 2023

Keywords

Crossrefs

Programs

  • Maple
    A364762 := proc(n)
        add( (-1)^k*binomial(n+1,k) * binomial(4*k,n-k),k=0..n) ;
        %/(n+1) ;
    end proc:
    seq(A364762(n),n=0..80); # R. J. Mathar, Aug 10 2023
  • Mathematica
    nmax = 26; A[_] = 1;
    Do[A[x_] = 1/(1 + x*(1 + x*A[x])^4) + O[x]^(nmax+1) // Normal, {nmax}];
    CoefficientList[A[x], x] (* Jean-François Alcover, Oct 25 2023 *)
  • PARI
    a(n) = sum(k=0, n, (-1)^k*binomial(n+1, k)*binomial(4*k, n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} (-1)^k * binomial(n+1,k) * binomial(4*k,n-k).
D-finite with recurrence -128*(2042050230119155915444*n -5429570252206459161379) *(4*n-1) *(2*n-1) *(4*n+5)*(n+1)*a(n) -32*(4*n+1) *(65345607363812989294208*n^4 -820413627047532146653920*n^3 +2763432436839800464356384*n^2 -2486292999757610914452558*n +135739256305161479034475)*a(n-1) +8*(25399908186485156187685696*n^5 -410520476995365688927070656*n^4 +1936659722310862831127714364*n^3 -3768407393014943668311778228*n^2 +3142503008733048326160670659*n -930530980753641871942147310)*a(n-2) +8*(60470966262814634790914176*n^5 -790603842787360719473560256*n^4 +4054580849567079779066278696*n^3 -10338573837841237994265694136*n^2 +13166278761352336081219763480*n-6688902526339456521313590345) *a(n-3) +8*(n-3) *(889289782697551916285417600*n^4 -9728080580320392023685701600*n^3 +38817722034818423528174576784*n^2 -65825556954123813925639696248*n +38902971323615633483566471005) *a(n-4) +8*(n-3) *(n-4)*(2097428215364339549126292456*n^3 -18251533871703386700639649538*n^2 +48220538425138794332555786686*n -34290240482247293887531480365) *a(n-5) +32*(n-3) *(n-4)*(n-5) *(468447167338832041688699407*n^2 -2522399644542316934351318150*n +2141819455274094692083493160) *a(n-6) +3381*(1381857597101978034513050*n -1395473045717316216699133) *(n-3)*(n-4) *(n-5)*(n-6)*a(n-7)=0. - R. J. Mathar, Aug 10 2023

A378731 G.f. A(x) satisfies A(x) = ( 1 + x / (1 - x*A(x)^(4/3)) )^3.

Original entry on oeis.org

1, 3, 6, 22, 93, 417, 1993, 9864, 50217, 261239, 1382448, 7418877, 40278175, 220830513, 1220930337, 6799458685, 38107621704, 214771481163, 1216457185122, 6920603372448, 39529745832681, 226605757331904, 1303291125124071, 7518151040142000, 43488151271999326
Offset: 0

Views

Author

Seiichi Manyama, Dec 05 2024

Keywords

Crossrefs

Programs

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

Formula

G.f.: A(x) = (1 + x*B(x))^3 where B(x) is the g.f. of A364743.
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(n+(s-1)*k-1,n-k)/(t*k+u*(n-k)+r).

A378732 G.f. A(x) satisfies A(x) = ( 1 + x / (1 - x*A(x)) )^4.

Original entry on oeis.org

1, 4, 10, 36, 155, 704, 3384, 16844, 86097, 449344, 2384170, 12822556, 69743953, 382982940, 2120323014, 11822279232, 66327376437, 374162700460, 2120999728610, 12075668658000, 69021358842795, 395909382981572, 2278286453089574, 13149207655326372, 76096242994616990
Offset: 0

Views

Author

Seiichi Manyama, Dec 05 2024

Keywords

Crossrefs

Programs

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

Formula

G.f.: A(x) = (1 + x*B(x))^4 where B(x) is the g.f. of A364743.
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(n+(s-1)*k-1,n-k)/(t*k+u*(n-k)+r).
Showing 1-6 of 6 results.