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.

A371460 Binomial transform of A355409.

Original entry on oeis.org

1, 2, 10, 80, 838, 10952, 171910, 3148280, 65890198, 1551389192, 40586247910, 1167964662680, 36666464437558, 1247011549249832, 45672691012357510, 1792280373542404280, 75021202465129000918, 3336499249170658956872, 157116438405334017308710, 7809681380575733223237080, 408621675981135189773468278
Offset: 0

Views

Author

Prabha Sivaramannair, Mar 24 2024

Keywords

Crossrefs

Cf. A355409.

Programs

  • SageMath
    def a(n):
        if n==0:
            return 1
        else:
            return (-1)^n + sum([(1-(-2)^j)*binomial(n,j)*a(n-j) for j in [1,..,n]])
    list(a(n) for n in [0,..,20])
    
  • SageMath
    f= e^(x)/(1 + e^(2*x) - e^(3*x))
    print([(diff(f,x,i)).subs(x=0) for i in [0,..,20]])

Formula

a(0) = 1, a(n) = (-1)^n + Sum_{j=1..n} (1-(-2)^j)*binomial(n,j)*a(n-j) for n > 0.
a(0) = 1, a(n) = 1 + Sum_{j=1..n} (3^j-2^j)*binomial(n,j)*a(n-j) for n > 0.
E.g.f.: exp(x)/(1 + exp(2*x) - exp(3*x)).

A355408 Expansion of e.g.f. 1/(1 + exp(x) - exp(3*x)).

Original entry on oeis.org

1, 2, 16, 170, 2416, 42962, 916696, 22819610, 649207456, 20778364322, 738918769576, 28905116527850, 1233506128752496, 57025618592932082, 2839117599033828856, 151446758367400488890, 8617182795217834505536, 520954229292164353554242
Offset: 0

Views

Author

Seiichi Manyama, Jul 01 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1+exp(x)-exp(3*x))))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (3^j-1)*binomial(i, j)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (3^k - 1) * binomial(n,k) * a(n-k).
a(n) ~ n! / ((3 + 2*r) * log(r)^(n+1)), where r = 2*cosh(log((25 + 3*sqrt(69)) / 2) / 6)/sqrt(3). - Vaclav Kotesovec, Jul 01 2022

A355411 Expansion of e.g.f. 1/(3 - exp(2*x) - exp(3*x)).

Original entry on oeis.org

1, 5, 63, 1175, 29211, 907775, 33852603, 1472830175, 73232729451, 4096474833695, 254608472798043, 17407167078420575, 1298290575826434891, 104900562662494154015, 9127848307446874753083, 850985644429074730049375, 84626187772620135685119531
Offset: 0

Views

Author

Seiichi Manyama, Jul 01 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(3-exp(2*x)-exp(3*x))))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (3^j+2^j)*binomial(i, j)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (3^k + 2^k) * binomial(n,k) * a(n-k).
a(n) ~ n! / ((9 - r^2) * log(r)^(n+1)), where r = (-1 + 2*cosh(log((79 + 9*sqrt(77))/2)/3))/3. - Vaclav Kotesovec, Jul 01 2022

A368015 Expansion of e.g.f. 1/(1 - exp(2*x) + exp(3*x)).

Original entry on oeis.org

1, -1, -3, 5, 81, 29, -4623, -20035, 415041, 4838909, -46093743, -1309934275, 3230184801, 419574363389, 2065056788337, -154120122603715, -2307971235744639, 59954627542249469, 1959892188447337617, -19474957767402204355, -1658215397958862557279
Offset: 0

Views

Author

Seiichi Manyama, Dec 08 2023

Keywords

Crossrefs

Cf. A355409.

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (2^j-3^j)*binomial(i, j)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (2^k - 3^k) * binomial(n,k) * a(n-k).
Showing 1-4 of 4 results.