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 1-5 of 5 results.

A362478 E.g.f. satisfies A(x) = exp(x + x^3/3 * A(x)^3).

Original entry on oeis.org

1, 1, 1, 3, 33, 321, 2841, 31641, 498849, 8979489, 167510961, 3427780401, 80374833441, 2089382321313, 58020408889353, 1721768971537161, 55150870311938241, 1897482353016075201, 69322763655015214689, 2676706914491568918369
Offset: 0

Views

Author

Seiichi Manyama, Apr 21 2023

Keywords

Crossrefs

Column k=2 of A362490.
Cf. A362390.

Programs

  • Mathematica
    nmax = 20; A[_] = 1;
    Do[A[x_] = Exp[x + x^3/3*A[x]^3] + O[x]^(nmax+1) // Normal, {nmax}];
    CoefficientList[A[x], x]*Range[0, nmax]! (* Jean-François Alcover, Mar 04 2024 *)
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-x^3*exp(3*x))/3)))

Formula

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

A362472 E.g.f. satisfies A(x) = exp(x + x^3 * A(x)^3).

Original entry on oeis.org

1, 1, 1, 7, 97, 961, 10201, 177241, 3801505, 80718625, 1887205681, 52896262321, 1648697978401, 54216677033377, 1928791931034697, 75326014326206281, 3159713152034201281, 140373558362282197441, 6632746205445950124385, 333591744669464008432225
Offset: 0

Views

Author

Seiichi Manyama, Apr 21 2023

Keywords

Crossrefs

Column k=6 of A362490.

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-3*x^3*exp(3*x))/3)))

Formula

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

A362477 E.g.f. satisfies A(x) = exp(x + x^3/6 * A(x)^3).

Original entry on oeis.org

1, 1, 1, 2, 17, 161, 1351, 12391, 153385, 2388905, 40060781, 708351821, 13861042801, 305141790097, 7339275555067, 188198812659131, 5143808931521681, 150713978752271441, 4718460264313196665, 156524510548008965305, 5474266337362911068161
Offset: 0

Views

Author

Seiichi Manyama, Apr 21 2023

Keywords

Crossrefs

Column k=1 of A362490.
Cf. A362381.

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-x^3/2*exp(3*x))/3)))

Formula

E.g.f.: exp(x - LambertW(-x^3/2 * exp(3*x))/3) = ( -2 * LambertW(-x^3/2 * exp(3*x))/x^3 )^(1/3).
a(n) = n! * Sum_{k=0..floor(n/3)} (1/6)^k * (3*k+1)^(n-2*k-1) / (k! * (n-3*k)!).

A362479 E.g.f. satisfies A(x) = exp(x + x^3/2 * A(x)^3).

Original entry on oeis.org

1, 1, 1, 4, 49, 481, 4471, 57751, 1036393, 19939753, 399150541, 9082285741, 237719388721, 6759766432849, 204408880370059, 6672899023062091, 236080878357745681, 8926817568378582481, 357421258163575234873, 15158257732928974255993
Offset: 0

Views

Author

Seiichi Manyama, Apr 21 2023

Keywords

Crossrefs

Column k=3 of A362490.
Cf. A362391.

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-3*x^3/2*exp(3*x))/3)))

Formula

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

A362483 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) = n! * Sum_{j=0..floor(n/2)} (k/2)^j * (2*j+1)^(n-j-1) / (j! * (n-2*j)!).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 10, 1, 1, 1, 4, 19, 70, 1, 1, 1, 5, 28, 169, 646, 1, 1, 1, 6, 37, 298, 2041, 7576, 1, 1, 1, 7, 46, 457, 4186, 30811, 106744, 1, 1, 1, 8, 55, 646, 7081, 74116, 560827, 1761628, 1, 1, 1, 9, 64, 865, 10726, 141901, 1578340, 11957905, 33361948, 1
Offset: 0

Views

Author

Seiichi Manyama, Apr 21 2023

Keywords

Examples

			Square array begins:
  1,   1,    1,    1,    1,     1, ...
  1,   1,    1,    1,    1,     1, ...
  1,   2,    3,    4,    5,     6, ...
  1,  10,   19,   28,   37,    46, ...
  1,  70,  169,  298,  457,   646, ...
  1, 646, 2041, 4186, 7081, 10726, ...
		

Crossrefs

Columns k=0..3 give A000012, A362474, A143768, A362475.

Programs

  • PARI
    T(n, k) = n! * sum(j=0, n\2, (k/2)^j*(2*j+1)^(n-j-1)/(j!*(n-2*j)!));

Formula

E.g.f. A_k(x) of column k satisfies A_k(x) = exp(x + k*x^2/2 * A_k(x)^2).
A_k(x) = exp(x - LambertW(-k*x^2 * exp(2*x))/2).
A_k(x) = sqrt( -LambertW(-k*x^2 * exp(2*x))/(k*x^2) ) for k > 0.
Showing 1-5 of 5 results.