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.

A353546 Expansion of e.g.f. -log(1-2*x) * exp(x)/2.

Original entry on oeis.org

0, 1, 4, 17, 96, 729, 7060, 83033, 1146656, 18164625, 324488068, 6450956929, 141233271872, 3376008830505, 87480173354964, 2442396780039817, 73089894980585408, 2333809837398044321, 79198287879591647364, 2846319497398561356913
Offset: 0

Views

Author

Seiichi Manyama, May 27 2022

Keywords

Crossrefs

Cf. A346394.
Essentially partial sums of A010844.

Programs

  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(-log(1-2*x)*exp(x)/2)))
    
  • PARI
    a(n) = n!*sum(k=0, n-1, 2^(n-1-k)/((n-k)*k!));
    
  • PARI
    a_vector(n) = my(v=vector(n+1, i, if(i==2, 1, 0))); for(i=2, n, v[i+1]=(2*i-1)*v[i]-2*(i-1)*v[i-1]+1); v;

Formula

a(n) = n! * Sum_{k=0..n-1} 2^(n-1-k) / ((n-k) * k!).
a(0) = 0, a(1) = 1, a(n) = (2 * n - 1) * a(n-1) - 2 * (n-1) * a(n-2) + 1.
a(n) ~ (n-1)! * exp(1/2) * 2^(n-1). - Vaclav Kotesovec, Jun 08 2022

A353548 Expansion of e.g.f. -log(1-4*x) * exp(x)/4.

Original entry on oeis.org

0, 1, 6, 47, 540, 8429, 166210, 3952955, 109981816, 3502905369, 125648153278, 5011458069639, 219987094389524, 10538817637744005, 547118005892177018, 30595552548140425747, 1833501625083035349488, 117219490267316310468913
Offset: 0

Views

Author

Seiichi Manyama, May 27 2022

Keywords

Crossrefs

Cf. A346396.
Essentially partial sums of A056545.

Programs

  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(-log(1-4*x)*exp(x)/4)))
    
  • PARI
    a(n) = n!*sum(k=0, n-1, 4^(n-1-k)/((n-k)*k!));
    
  • PARI
    a_vector(n) = my(v=vector(n+1, i, if(i==2, 1, 0))); for(i=2, n, v[i+1]=(4*i-3)*v[i]-4*(i-1)*v[i-1]+1); v;

Formula

a(n) = n! * Sum_{k=0..n-1} 4^(n-1-k) / ((n-k) * k!).
a(0) = 0, a(1) = 1, a(n) = (4 * n - 3) * a(n-1) - 4 * (n-1) * a(n-2) + 1.
a(n) ~ (n-1)! * exp(1/4) * 4^(n-1). - Vaclav Kotesovec, Jun 08 2022

A353549 Expansion of e.g.f. log(1+3*x) * exp(x)/3.

Original entry on oeis.org

0, 1, -1, 12, -104, 1289, -19605, 356488, -7541464, 182009385, -4935863537, 148600324124, -4918093868688, 177482897072545, -6936155749635541, 291836667412104072, -13152940374866178512, 632196357654491385521, -32280617841842744380161
Offset: 0

Views

Author

Seiichi Manyama, May 27 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(log(1+3*x)*exp(x)/3)))
    
  • PARI
    a(n) = n!*sum(k=0, n-1, (-3)^(n-1-k)/((n-k)*k!));
    
  • PARI
    a_vector(n) = my(v=vector(n+1, i, if(i==2, 1, 0))); for(i=2, n, v[i+1]=(-3*i+4)*v[i]+3*(i-1)*v[i-1]+1); v;

Formula

a(n) = n! * Sum_{k=0..n-1} (-3)^(n-1-k) / ((n-k) * k!).
a(0) = 0, a(1) = 1, a(n) = (-3 * n + 4) * a(n-1) + 3 * (n-1) * a(n-2) + 1.
a(n) ~ -(-1)^n * (n-1)! * 3^(n-1) / exp(1/3). - Vaclav Kotesovec, Jun 08 2022

A354419 Expansion of e.g.f. log(1+4*x) * exp(x)/4.

Original entry on oeis.org

0, 1, -2, 23, -276, 4509, -91190, 2205587, -62104168, 1995807993, -72089029802, 2891304481999, -127498010037244, 6131189086886421, -319320539953144158, 17905976286288568267, -1075611833288214177232, 68909527979479961534705
Offset: 0

Views

Author

Seiichi Manyama, May 27 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(log(1+4*x)*exp(x)/4)))
    
  • PARI
    a(n) = n!*sum(k=0, n-1, (-4)^(n-1-k)/((n-k)*k!));
    
  • PARI
    a_vector(n) = my(v=vector(n+1, i, if(i==2, 1, 0))); for(i=2, n, v[i+1]=(-4*i+5)*v[i]+4*(i-1)*v[i-1]+1); v;

Formula

a(n) = n! * Sum_{k=0..n-1} (-4)^(n-1-k) / ((n-k) * k!).
a(0) = 0, a(1) = 1, a(n) = (-4 * n + 5) * a(n-1) + 4 * (n-1) * a(n-2) + 1.
a(n) ~ -(-1)^n * (n-1)! * 4^(n-1) / exp(1/4). - Vaclav Kotesovec, Jun 08 2022
Showing 1-4 of 4 results.