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.

A384894 G.f. A(x) satisfies A(x) = 1 + x/A(-x*A(x))^2.

Original entry on oeis.org

1, 1, 2, 1, -4, -14, -30, 12, 330, 1139, 2226, -2288, -39646, -163742, -410900, -89273, 5352720, 31177720, 114624554, 234094417, -312845870, -5584935715, -32878240028, -127407695297, -315375599410, 24759230680, 6177102106748, 44838273448641, 220383314338200
Offset: 0

Views

Author

Seiichi Manyama, Jun 12 2025

Keywords

Crossrefs

Column k=1 of A384899.
Cf. A213091.

Programs

  • PARI
    a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-n+2*j+k-1, j-1)*a(n-j, 2*j)/j));

Formula

See A384899.

A384944 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A384941.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 4, 0, 1, 3, 9, -2, 0, 1, 4, 15, 4, -64, 0, 1, 5, 22, 19, -116, -95, 0, 1, 6, 30, 44, -144, -334, 780, 0, 1, 7, 39, 80, -135, -675, 862, 5230, 0, 1, 8, 49, 128, -75, -1060, 70, 11516, 19228, 0, 1, 9, 60, 189, 51, -1414, -1684, 16953, 59632, -90488, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 13 2025

Keywords

Examples

			Square array begins:
  1,   1,    1,    1,     1,     1,     1, ...
  0,   1,    2,    3,     4,     5,     6, ...
  0,   4,    9,   15,    22,    30,    39, ...
  0,  -2,    4,   19,    44,    80,   128, ...
  0, -64, -116, -144,  -135,   -75,    51, ...
  0, -95, -334, -675, -1060, -1414, -1644, ...
  0, 780,  862,   70, -1684, -4380, -7869, ...
		

Crossrefs

Columns k=0..1 give A000007, A384941.

Programs

  • PARI
    b(n, k) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-n+2*j+k-1, j-1)*b(n-j, 4*j)/j));
    a(n, k) = b(n, -k);

Formula

Let b(n,k) = 0^n if n*k=0, otherwise b(n,k) = (-1)^n * k * Sum_{j=1..n} binomial(-n+2*j+k-1,j-1) * b(n-j,4*j)/j. Then A(n,k) = b(n,-k).

A384945 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A384942.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 5, 0, 1, 3, 11, -5, 0, 1, 4, 18, 0, -135, 0, 1, 5, 26, 16, -255, -110, 0, 1, 6, 35, 44, -345, -540, 3661, 0, 1, 7, 45, 85, -389, -1230, 5777, 16440, 0, 1, 8, 56, 140, -370, -2100, 5918, 40452, -1375, 0, 1, 9, 68, 210, -270, -3049, 3784, 67356, 86065, -827075, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 13 2025

Keywords

Examples

			Square array begins:
  1,    1,    1,     1,     1,     1,     1, ...
  0,    1,    2,     3,     4,     5,     6, ...
  0,    5,   11,    18,    26,    35,    45, ...
  0,   -5,    0,    16,    44,    85,   140, ...
  0, -135, -255,  -345,  -389,  -370,  -270, ...
  0, -110, -540, -1230, -2100, -3049, -3954, ...
  0, 3661, 5777,  5918,  3784,  -770, -7708, ...
		

Crossrefs

Columns k=0..1 give A000007, A384942.

Programs

  • PARI
    b(n, k) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-n+2*j+k-1, j-1)*b(n-j, 5*j)/j));
    a(n, k) = b(n, -k);

Formula

Let b(n,k) = 0^n if n*k=0, otherwise b(n,k) = (-1)^n * k * Sum_{j=1..n} binomial(-n+2*j+k-1,j-1) * b(n-j,5*j)/j. Then A(n,k) = b(n,-k).

A384946 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A384943.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 6, 0, 1, 3, 13, -9, 0, 1, 4, 21, -6, -244, 0, 1, 5, 30, 10, -470, -39, 0, 1, 6, 40, 40, -660, -674, 11262, 0, 1, 7, 51, 85, -795, -1824, 19599, 36971, 0, 1, 8, 63, 146, -855, -3384, 24171, 100390, -268890, 0, 1, 9, 76, 224, -819, -5224, 24318, 180627, -268456, -3724293, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 13 2025

Keywords

Examples

			Square array begins:
  1,     1,     1,     1,     1,     1,     1, ...
  0,     1,     2,     3,     4,     5,     6, ...
  0,     6,    13,    21,    30,    40,    51, ...
  0,    -9,    -6,    10,    40,    85,   146, ...
  0,  -244,  -470,  -660,  -795,  -855,  -819, ...
  0,   -39,  -674, -1824, -3384, -5224, -7188, ...
  0, 11262, 19599, 24171, 24318, 19590,  9778, ...
		

Crossrefs

Columns k=0..1 give A000007, A384943.

Programs

  • PARI
    b(n, k) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-n+2*j+k-1, j-1)*b(n-j, 6*j)/j));
    a(n, k) = b(n, -k);

Formula

Let b(n,k) = 0^n if n*k=0, otherwise b(n,k) = (-1)^n * k * Sum_{j=1..n} binomial(-n+2*j+k-1,j-1) * b(n-j,6*j)/j. Then A(n,k) = b(n,-k).
Showing 1-4 of 4 results.