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.

A377742 E.g.f. satisfies A(x) = exp(x) / (1 - x * A(x))^2.

Original entry on oeis.org

1, 3, 23, 331, 7133, 205901, 7470475, 326932299, 16768124217, 986753701657, 65548017270791, 4852285640543639, 396133183892522389, 35359325061987638661, 3426053898460864501251, 358128187005971803014211, 40172982580368589391407217, 4813677071886578522596221233
Offset: 0

Views

Author

Seiichi Manyama, Nov 05 2024

Keywords

Crossrefs

Programs

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

Formula

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

A377811 E.g.f. satisfies A(x) = exp(x * A(x)) / (1 - x)^3.

Original entry on oeis.org

1, 4, 27, 283, 4217, 82971, 2041855, 60475885, 2096566449, 83324680435, 3736041351311, 186594364199277, 10274269171279657, 618386703880855339, 40393224245061185919, 2846030947359659421901, 215160957844217080056161, 17373449685399138641312739, 1492298627191467511376377999
Offset: 0

Views

Author

Seiichi Manyama, Nov 08 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(-lambertw(-x/(1-x)^3))/(1-x)^3))
    
  • PARI
    a(n) = n!*sum(k=0, n, (k+1)^(k-1)*binomial(n+2*k+2, n-k)/k!);

Formula

E.g.f.: exp( -LambertW(-x/(1-x)^3) )/(1-x)^3.
E.g.f.: -LambertW(-x/(1-x)^3)/x.
a(n) = n! * Sum_{k=0..n} (k+1)^(k-1) * binomial(n+2*k+2,n-k)/k!.

A377833 Expansion of e.g.f. (1/x) * Series_Reversion( x * (1 - x)^3 * exp(-x) ).

Original entry on oeis.org

1, 4, 51, 1174, 39833, 1799136, 101821723, 6938396368, 553482404721, 50619262481920, 5223014483031491, 600332651141435136, 76075005337204547209, 10538051760153093320704, 1584264031801742560408875, 256912816791069951740348416, 44703731640012047610981808097
Offset: 0

Views

Author

Seiichi Manyama, Nov 09 2024

Keywords

Crossrefs

Programs

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

Formula

E.g.f. A(x) satisfies A(x) = exp(x * A(x))/(1 - x*A(x))^3.
a(n) = n! * Sum_{k=0..n} (n+1)^(k-1) * binomial(4*n-k+2,n-k)/k!.

A377744 E.g.f. satisfies A(x) = exp(x) / (1 - x * A(x))^4.

Original entry on oeis.org

1, 5, 69, 1741, 65025, 3238401, 202252549, 15216086789, 1340493558497, 135418524663457, 15436319894361141, 1960277599669850517, 274474966233168968353, 42012725272366653895169, 6979546631782182590117189, 1250777360824265136694022341, 240516661686854988775792192833
Offset: 0

Views

Author

Seiichi Manyama, Nov 06 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n, (k+1)^(n-k-1)*binomial(5*k+3, k)/(n-k)!);

Formula

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