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 11-18 of 18 results.

A277483 E.g.f.: -arcsin(x)*LambertW(-x).

Original entry on oeis.org

0, 0, 2, 6, 40, 340, 3984, 57050, 982528, 19616328, 446355840, 11384327438, 321701896704, 9973046260060, 336499112011776, 12274383608508450, 481282311712489472, 20185816487436968208, 901732370496365076480, 42742176871086712813974, 2142556308913381810012160
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-ArcSin[x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!
    Flatten[{0, Table[Sum[Binomial[n, k] * (1-(-1)^k)/2 * (k-2)!!^2 * (n-k)^(n-k-1), {k, 1, n-1}], {n, 1, 20}]}] (* Vaclav Kotesovec, Oct 28 2016 *)
  • PARI
    x='x+O('x^50); concat([0,0], Vec(serlaplace(- asin(x)*lambertw(-x) ))) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) ~ arcsin(exp(-1)) * n^(n-1).

A277485 E.g.f.: -exp(2*x)*LambertW(-x).

Original entry on oeis.org

0, 1, 6, 33, 216, 1865, 21228, 303765, 5222864, 104540337, 2383558740, 60933722069, 1725392415288, 53590463856345, 1811281159509500, 66172416761172885, 2598298697830360992, 109116931783034360801, 4880122696811960470692, 231565260558289051906965
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-Exp[2*x]*LambertW[-x], {x, 0, 20}], x]*Range[0, 20]!
    Table[Sum[Binomial[n, m]*Sum[Binomial[m, k]*k^(k-1), {k, 1, m}], {m, 1, n}], {n, 0, 20}]
  • PARI
    x='x+O('x^50); concat([0], Vec(serlaplace(- exp(2*x)*lambertw(-x) ))) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) = Sum_{m=1..n} (binomial(n,m) * Sum_{k=1..m} binomial(m,k)*k^(k-1)).
a(n) ~ exp(2*exp(-1)) * n^(n-1).

A277481 E.g.f.: -log(1+x)*LambertW(-x).

Original entry on oeis.org

0, 0, 2, 3, 32, 240, 3114, 44065, 777720, 15582168, 357427770, 9151281293, 259607392164, 8070381333872, 272960010908662, 9976300661919345, 391837137436921072, 16458193396472517328, 736145006794621566642, 34932117830021859779517, 1752782822664497750549660
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-Log[1+x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!
    Table[n!*Sum[(-1)^(n-k-1)*k^(k-1)/(k!*(n-k)), {k, 1, n-1}], {n, 0, 20}] (* Vaclav Kotesovec, Oct 28 2016 *)
  • PARI
    x='x+O('x^50); concat([0,0], Vec(serlaplace(-log(1+x)*lambertw(-x) ))) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) ~ log(1+exp(-1)) * n^(n-1).

A277482 E.g.f.: log(1-x)*LambertW(-x).

Original entry on oeis.org

0, 0, 2, 9, 56, 480, 5394, 75775, 1280376, 25270056, 569899770, 14444562803, 406204015524, 12545427045008, 422007399953398, 15354968442741135, 600807449737710832, 25153741340051795248, 1121917008608064151218, 53107023489332468636739, 2658946993059795072656540
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Log[1-x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!
    Table[n!*Sum[k^(k-1)/(k!*(n-k)), {k, 1, n-1}], {n, 0, 20}] (* Vaclav Kotesovec, Oct 28 2016 *)
  • PARI
    x='x+O('x^50); concat([0,0], Vec(serlaplace(log(1-x)*lambertw(-x)) )) \\ G. C. Greubel, Nov 09 2017

Formula

a(n) ~ -log(1-exp(-1)) * n^(n-1).

A277484 E.g.f.: -arcsinh(x)*LambertW(-x).

Original entry on oeis.org

0, 0, 2, 6, 32, 300, 3624, 52570, 908928, 18277560, 417634080, 10682763278, 302517156864, 9394763009060, 317429118686848, 11592017133950370, 454961391572119552, 19097430979664893168, 853711115246721262080, 40490675416206345889686, 2030782746261324446228480
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-ArcSinh[x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!
    Flatten[{0, Table[Sum[Sin[Pi*k/2] * Binomial[n, k] * (k-2)!!^2 * (n-k)^(n-k-1), {k, 1, n-1}], {n, 1, 20}]}] (* Vaclav Kotesovec, Oct 28 2016 *)
  • PARI
    x='x+O('x^10); concat([0,0], Vec(serlaplace(-asinh(x)*lambertw(-x) ))) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) ~ arcsinh(exp(-1)) * n^(n-1).
a(n) ~ (-1 + log(1 + sqrt(1+exp(2)))) * n^(n-1).

A294411 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. -exp(k*x)*LambertW(-x).

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 1, 4, 9, 0, 1, 6, 18, 64, 0, 1, 8, 33, 116, 625, 0, 1, 10, 54, 216, 1060, 7776, 0, 1, 12, 81, 388, 1865, 12702, 117649, 0, 1, 14, 114, 656, 3340, 21228, 187810, 2097152, 0, 1, 16, 153, 1044, 5905, 36414, 303765, 3296120, 43046721, 0, 1, 18, 198, 1576, 10100, 63480, 500374, 5222864, 66897288, 1000000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 30 2017

Keywords

Examples

			E.g.f. of column k: A_k(x) = x/1! + 2*(k + 1)*x^2/2! + 3*(k^2 + 2*k + 3)*x^3/3! + 4*(k^3 + 3*k^2 + 9*k + 16)*x^4/4! + ...
Square array begins:
    0,     0,     0,     0,     0,      0, ...
    1,     1,     1,     1,     1,      1, ...
    2,     4,     6,     8,    10,     12, ...
    9,    18,    33,    54,    81,    114, ...
   64,   116,   216,   388,   656,   1044, ...
  625,  1060,  1895,  3340,  5905,  10100, ...
		

Crossrefs

Columns k=0..2 give A000169, A277473, A277485.
Main diagonal gives A292633.
Cf. A290824.

Programs

  • Mathematica
    Table[Function[k, n! SeriesCoefficient[-Exp[k x] LambertW[-x], {x, 0, n}]][j - n], {j, 0, 10}, {n, 0, j}] // Flatten

Formula

E.g.f. of column k: -exp(k*x)*LambertW(-x).

A372333 Expansion of e.g.f. -exp(x) * LambertW(-2*x)/2.

Original entry on oeis.org

0, 1, 6, 51, 684, 12965, 317298, 9500631, 336237016, 13729172553, 635237632350, 32844916975739, 1876755685038468, 117437155609780461, 7986793018367861194, 586578825469711599135, 46268265552518066488752, 3901008402618593931019409
Offset: 0

Views

Author

Seiichi Manyama, Apr 28 2024

Keywords

Crossrefs

Programs

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

Formula

a(n) = Sum_{k=1..n} (2*k)^(k-1) * binomial(n,k).
G.f.: Sum_{k>=1} (2*k)^(k-1) * x^k / (1-x)^(k+1).
a(n) ~ exp(exp(-1)/2) * 2^(n-1) * n^(n-1). - Vaclav Kotesovec, Apr 30 2024

A372334 Expansion of e.g.f. -exp(x) * LambertW(-3*x)/3.

Original entry on oeis.org

0, 1, 8, 102, 2092, 60140, 2220954, 100119670, 5328468968, 326960686872, 22724388453070, 1764411577328906, 151364204180518476, 14217940294767407380, 1451334877597451677250, 159972528561402504191190, 18936257811933773637390544, 2395818853376147403857700656
Offset: 0

Views

Author

Seiichi Manyama, Apr 28 2024

Keywords

Crossrefs

Programs

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

Formula

a(n) = Sum_{k=1..n} (3*k)^(k-1) * binomial(n,k).
G.f.: Sum_{k>=1} (3*k)^(k-1) * x^k / (1-x)^(k+1).
a(n) ~ exp(exp(-1)/3) * 3^(n-1) * n^(n-1). - Vaclav Kotesovec, Apr 30 2024
Previous Showing 11-18 of 18 results.