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 1-2 of 2 results.

A354518 Expansion of e.g.f. cosh(x)^exp(x).

Original entry on oeis.org

1, 0, 1, 3, 7, 30, 166, 798, 4117, 27660, 196756, 1328448, 9866407, 86205210, 759842266, 6460661028, 60841732777, 651349676280, 6795873687496, 67981177154688, 770224145659627, 9854500496860470, 116983085896035646, 1301594922821009028, 17440543467561038557
Offset: 0

Views

Author

Seiichi Manyama, Aug 16 2022

Keywords

Comments

a(39) is negative. - Vaclav Kotesovec, Aug 17 2022

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(cosh(x)^exp(x)))
    
  • PARI
    a354520(n) = sum(k=1, n\2, (16^k-4^k)*bernfrac(2*k)/(2*k)*binomial(n, 2*k));
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, a354520(j)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A354520(k) * binomial(n-1,k-1) * a(n-k).

A215515 2n-th derivative of cos(x)^cos(x) at x=0.

Original entry on oeis.org

1, -1, 7, -76, 1597, -41776, 1673167, -74527636, 4832747017, -305644428256, 30618856073947, -2276081971574236, 390042814538656957, -20435946140834126176, 10544180964356207226247, 604793906292405974180324, 688972694565220644332739217
Offset: 0

Views

Author

Michel Lagneau, Aug 14 2012

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> coeff(series(cos(x)^cos(x), x, 2*n+1), x, 2*n)*(2*n)!:
    seq(a(n), n=0..21);  # Alois P. Heinz, Apr 17 2023
  • Mathematica
    f[x_] := Cos[x]^Cos[x]; Table[Derivative[2*n][f][0],{n,0,30}]
  • PARI
    a354520(n) = sum(k=1, n\2, (16^k-4^k)*bernfrac(2*k)/(2*k)*binomial(n, 2*k));
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (-1)^j*a354520(2*j)*binomial(2*i-1, 2*j-1)*v[i-j+1])); v; \\ Seiichi Manyama, Aug 17 2022

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (-1)^k * A354520(2*k) * binomial(2*n-1,2*k-1) * a(n-k). - Seiichi Manyama, Aug 17 2022
Showing 1-2 of 2 results.