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.

A384760 E.g.f. A(x) satisfies A(x) = exp( -x*A(x) * A(-x*A(x)) ).

Original entry on oeis.org

1, -1, 1, 5, -35, -281, 5671, 42671, -2179127, -9146017, 1529743051, -2876300681, -1703719191635, 19006164045023, 2748187169359087, -67807538576332801, -6002760779933693039, 267196356696377129023, 16763997717087046669459, -1258157898725874129675001
Offset: 0

Views

Author

Seiichi Manyama, Jun 09 2025

Keywords

Examples

			E.g.f.: A(x) =  1 - x + x^2/2 + 5*x^3/6 - 35*x^4/24 - 281*x^5/120 + ...
A(x) * A(-x*A(x)) = 1 - 2*x^2/2 + 3*x^3/6 + 80*x^4/24 - 535*x^5/120 - ...
		

Crossrefs

Column k=1 of A384761.

Programs

  • PARI
    a(n, k=1) = if(k==0, 0^n, (-1)^n*k*sum(j=0, n, (n+k)^(j-1)*binomial(n, j)*a(n-j, j)));

Formula

See A384761.

A384758 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f. B(x)^k, where B(x) is the e.g.f. of A384757.

Original entry on oeis.org

1, 1, 0, 1, -1, 0, 1, -2, -1, 0, 1, -3, 0, 14, 0, 1, -4, 3, 34, 9, 0, 1, -5, 8, 54, -88, -1516, 0, 1, -6, 15, 68, -327, -3402, 4345, 0, 1, -7, 24, 70, -720, -4908, 30532, 507870, 0, 1, -8, 35, 54, -1255, -5044, 84321, 1027402, -4984063, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 09 2025

Keywords

Examples

			Square array begins:
  1,     1,     1,     1,     1,     1, ...
  0,    -1,    -2,    -3,    -4,    -5, ...
  0,    -1,     0,     3,     8,    15, ...
  0,    14,    34,    54,    68,    70, ...
  0,     9,   -88,  -327,  -720, -1255, ...
  0, -1516, -3402, -4908, -5044, -2700, ...
		

Crossrefs

Columns k=0..1 give A000007, A384757.
Cf. A384761.

Programs

  • PARI
    a(n, k) = if(k==0, 0^n, (-1)^n*k*sum(j=0, n, (n-j+k)^(j-1)*binomial(n, j)*a(n-j, j)));

Formula

A(n,0) = 0^n; A(n,k) = (-1)^n * k * Sum_{j=0..n} (n-j+k)^(j-1) * binomial(n,j) * A(n-j,j).
Showing 1-2 of 2 results.