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.

A362350 a(n) = n! * Sum_{k=0..floor(n/2)} (k/2)^k / (k! * (n-2*k)!).

Original entry on oeis.org

1, 1, 2, 4, 19, 71, 601, 3277, 39089, 277489, 4250341, 37110701, 693581197, 7184750509, 158461520309, 1899055549861, 48269252293201, 656869268651537, 18903165795857089, 287927838327392929, 9252988524143245181, 155954097639111859501
Offset: 0

Views

Author

Seiichi Manyama, Apr 17 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x)/(1+lambertw(-x^2/2))))

Formula

E.g.f.: exp(x) / (1 + LambertW(-x^2/2)).
a(n) ~ (exp(2^(3/2)*exp(-1/2)) + (-1)^n) * n^n / (2^((n+1)/2) * exp(n/2 + sqrt(2)*exp(-1/2))). - Vaclav Kotesovec, Apr 18 2023

A362352 a(n) = n! * Sum_{k=0..floor(n/4)} (k/24)^k / (k! * (n-4*k)!).

Original entry on oeis.org

1, 1, 1, 1, 2, 6, 16, 36, 211, 1387, 6511, 23431, 225721, 2207921, 14610597, 71848141, 958259121, 12403693681, 105819536881, 659686502257, 11235532306021, 180826378073461, 1888306425160541, 14256573124903341, 295428115205647117, 5683724892725141901
Offset: 0

Views

Author

Seiichi Manyama, Apr 17 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x)/(1+lambertw(-x^4/24))))

Formula

E.g.f.: exp(x) / (1 + LambertW(-x^4/24)).
a(n) ~ (exp(2^(3/4)*3^(1/4)*exp(-1/4)) + (-1)^n/exp(2^(3/4)*3^(1/4)*exp(-1/4)) + 2*cos(2^(3/4)*3^(1/4)*exp(-1/4) - Pi*n/2)) * n^n / (2^(3*n/4 + 1) * 3^(n/4) * exp(3*n/4)). - Vaclav Kotesovec, Apr 18 2023

A362705 Expansion of e.g.f. 1/(1 + LambertW(-x^3/6 * exp(x))).

Original entry on oeis.org

1, 0, 0, 1, 4, 10, 60, 595, 4536, 34524, 361320, 4333725, 51214460, 651628406, 9448719644, 146868322055, 2376666773040, 41077757951000, 762599081332176, 14918668387075449, 305774990501285940, 6602482711971622210, 149921553418087172260, 3557552268845721893131
Offset: 0

Views

Author

Seiichi Manyama, Apr 30 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1+lambertw(-x^3/6*exp(x)))))

Formula

a(n) = n! * Sum_{k=0..floor(n/3)} k^(n-2*k) / (6^k * k! * (n-3*k)!).

A362525 a(n) = n! * Sum_{k=0..floor(n/3)} (k+1)^(k-1) / (6^k * k! * (n-3*k)!).

Original entry on oeis.org

1, 1, 1, 2, 5, 11, 51, 246, 897, 7085, 51221, 260426, 2938541, 28279967, 184234415, 2714662406, 32614422401, 259026339161, 4721237878537, 67998862785970, 637019875964341, 13852253151455251, 232584488748665131, 2510358957337412182, 63466995535914172225
Offset: 0

Views

Author

Seiichi Manyama, Apr 23 2023

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-x^3/6))))

Formula

E.g.f.: exp(x - LambertW(-x^3/6)) = -6 * LambertW(-x^3/6)/x^3 * exp(x).
Showing 1-4 of 4 results.