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.

A330150 Expansion of e.g.f. exp(-x) / (1 - log(1 + x)).

Original entry on oeis.org

1, 0, 0, 1, -1, 8, -16, 159, -659, 6824, -46680, 517581, -4941685, 61043344, -735256328, 10269016939, -147207286503, 2322683458544, -38298239486672, 677630804946393, -12581447014620585, 247342217288517496, -5096876494438056928, 110338442309322274295
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 03 2019

Keywords

Comments

Inverse binomial transform of A006252.

Crossrefs

Programs

  • Mathematica
    nmax = 23; CoefficientList[Series[Exp[-x]/(1 - Log[1 + x]), {x, 0, nmax}], x] Range[0, nmax]!

Formula

a(n) = Sum_{k=0..n} (-1)^(n - k) * binomial(n,k) * A006252(k).
a(n) = (-1)^n + Sum_{k=1..n} (-1)^(k-1) * (k-1)! * binomial(n,k) * a(n-k). - Seiichi Manyama, Dec 19 2023

A291980 Triangle read by rows, T(n, k) = n!*[t^k] ([x^n] exp(x*t)/(1 - log(1+x))) for 0<=k<=n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 3, 3, 1, 4, 8, 6, 4, 1, 14, 20, 20, 10, 5, 1, 38, 84, 60, 40, 15, 6, 1, 216, 266, 294, 140, 70, 21, 7, 1, 600, 1728, 1064, 784, 280, 112, 28, 8, 1, 6240, 5400, 7776, 3192, 1764, 504, 168, 36, 9, 1
Offset: 0

Views

Author

Peter Luschny, Sep 15 2017

Keywords

Examples

			Triangle starts:
[1]
[1,      1]
[1,      2,    1]
[2,      3,    3,   1]
[4,      8,    6,   4,   1]
[14,    20,   20,  10,   5,   1]
[38,    84,   60,  40,  15,   6,  1]
[216,  266,  294, 140,  70,  21,  7, 1]
[600, 1728, 1064, 784, 280, 112, 28, 8, 1]
		

Crossrefs

Row sums: A291981.
Columns: A006252 (c=1), A108125 (c=2).
Diagonals: A000217 (d=3), A007290 (d=4), A033488 (d=5).
Cf. A291978.

Programs

  • Maple
    T_row := proc(n) exp(x*t)/(1 - log(1+x)): series(%, x, n+1):
    seq(n!*coeff(coeff(%,x,n), t, k), k=0..n) end:
    seq(T_row(n), n=0..10);
  • Mathematica
    T[n_, k_] := Binomial[n, n - k]*Sum[j!*StirlingS1[n - k, j], {j, 0, n - k}]; Flatten[Table[T[n, k], {n, 0, 9}, {k, 0, n}]] (* Detlef Meya, May 12 2024 *)

Formula

T(n, k) = binomial(n, n - k)*Sum_{j=0..n - k} j!*Stirling1(n - k, j). - Detlef Meya, May 12 2024

A305923 Expansion of e.g.f. exp(x)/(1 - log(1 + x) - log(1 + x)^2).

Original entry on oeis.org

1, 2, 6, 21, 105, 580, 4332, 33173, 333057, 3249334, 41175698, 485901669, 7470988137, 102962077608, 1870375878472, 29342124588357, 617978798588225, 10818920340476010, 260570216908845406, 5009431835664474101, 136578252867673635369, 2844357524328057280332, 87134882338620095240484
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 14 2018

Keywords

Comments

Binomial transform of A005444.
Sequence is signed: first negative term is a(61).

Examples

			E.g.f.: A(x) = 1 + 2*x/1! + 6*x^2/2! + 21*x^3/3! + 105*x^4/4! + 580*x^5/5! + 4332*x^6/6! + ...
		

Crossrefs

Programs

  • Maple
    a:=series(exp(x)/(1-log(1+x)-log(1+x)^2),x=0,23): seq(n!*coeff(a,x,n),n=0..22); # Paolo P. Lava, Mar 26 2019
  • Mathematica
    nmax = 22; CoefficientList[Series[Exp[x]/(1 - Log[1 + x] - Log[1 + x]^2), {x, 0, nmax}], x] Range[0, nmax]!
    Table[Sum[Sum[Binomial[n, k] StirlingS1[k, j] j! Fibonacci[j + 1], {j, 0, k}], {k, 0, n}], {n, 0, 22}]

Formula

a(n) = Sum_{k=0..n} Sum_{j=0..k} binomial(n,k)*Stirling1(k,j)*j!*Fibonacci(j+1).
a(n) ~ (-1)^n * n! * exp(exp(-phi) - phi^2) / (sqrt(5) * (1 - exp(-phi))^(n+1)), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Mar 26 2019

A368288 Expansion of e.g.f. exp(2*x) / (1 - log(1+x)).

Original entry on oeis.org

1, 3, 9, 28, 92, 326, 1262, 5412, 25720, 136208, 792432, 5105376, 35369072, 271130224, 2163931408, 19516167712, 172444938240, 1853022376064, 16940180000128, 231342744007680, 1864622339520768, 39188769208491520, 160619617213475840, 9585537940543741952, -35595308731629374464
Offset: 0

Views

Author

Seiichi Manyama, Dec 19 2023

Keywords

Crossrefs

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=2^i+sum(j=1, i, (-1)^(j-1)*(j-1)!*binomial(i, j)*v[i-j+1])); v;

Formula

a(n) = 2^n + Sum_{k=1..n} (-1)^(k-1) * (k-1)! * binomial(n,k) * a(n-k).

A368289 Expansion of e.g.f. exp(-2*x) / (1 - log(1 + x)).

Original entry on oeis.org

1, -1, 1, 0, -4, 22, -98, 508, -2952, 21040, -169360, 1579168, -16208784, 185045936, -2290934384, 30842081632, -445643595776, 6905128910976, -113892295743104, 1995421707848192, -36964967819409152, 722345322667829760, -14842592110869541888
Offset: 0

Views

Author

Seiichi Manyama, Dec 19 2023

Keywords

Crossrefs

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=(-2)^i+sum(j=1, i, (-1)^(j-1)*(j-1)!*binomial(i, j)*v[i-j+1])); v;

Formula

a(n) = (-2)^n + Sum_{k=1..n} (-1)^(k-1) * (k-1)! * binomial(n,k) * a(n-k).
Showing 1-5 of 5 results.