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.

A384581 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 A143501.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 4, 0, 1, 4, 6, 10, 16, 0, 1, 5, 10, 19, 41, 92, 0, 1, 6, 15, 32, 78, 224, 616, 0, 1, 7, 21, 50, 131, 411, 1464, 4729, 0, 1, 8, 28, 74, 205, 672, 2617, 11002, 40776, 0, 1, 9, 36, 105, 306, 1031, 4170, 19251, 93234, 388057, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 04 2025

Keywords

Examples

			Square array begins:
  1,   1,    1,    1,    1,    1,    1, ...
  0,   1,    2,    3,    4,    5,    6, ...
  0,   1,    3,    6,   10,   15,   21, ...
  0,   4,   10,   19,   32,   50,   74, ...
  0,  16,   41,   78,  131,  205,  306, ...
  0,  92,  224,  411,  672, 1031, 1518, ...
  0, 616, 1464, 2617, 4170, 6245, 8997, ...
		

Crossrefs

Columns k=0..1 give A000007, A143501.

Programs

  • PARI
    a(n, k) = if(k==0, 0^n, k*sum(j=0, n, binomial(3*n-3*j+k, j)/(3*n-3*j+k)*a(n-j, j)));

Formula

A(n,0) = 0^n; A(n,k) = k * Sum_{j=0..n} binomial(3*n-3*j+k,j)/(3*n-3*j+k) * A(n-j,j).

A384582 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 A384574.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 5, 0, 1, 4, 6, 12, 23, 0, 1, 5, 10, 22, 57, 155, 0, 1, 6, 15, 36, 105, 366, 1236, 0, 1, 7, 21, 55, 171, 651, 2853, 11286, 0, 1, 8, 28, 80, 260, 1032, 4951, 25584, 116333, 0, 1, 9, 36, 112, 378, 1536, 7656, 43587, 259789, 1329433, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 04 2025

Keywords

Examples

			Square array begins:
  1,    1,    1,    1,    1,     1,     1, ...
  0,    1,    2,    3,    4,     5,     6, ...
  0,    1,    3,    6,   10,    15,    21, ...
  0,    5,   12,   22,   36,    55,    80, ...
  0,   23,   57,  105,  171,   260,   378, ...
  0,  155,  366,  651, 1032,  1536,  2196, ...
  0, 1236, 2853, 4951, 7656, 11125, 15552, ...
		

Crossrefs

Columns k=0..1 give A000007, A384574.

Programs

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

Formula

A(n,0) = 0^n; A(n,k) = k * Sum_{j=0..n} binomial(4*n-4*j+k,j)/(4*n-4*j+k) * A(n-j,j).

A384583 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 A384575.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 6, 0, 1, 4, 6, 14, 31, 0, 1, 5, 10, 25, 75, 236, 0, 1, 6, 15, 40, 135, 546, 2166, 0, 1, 7, 21, 60, 215, 951, 4902, 22722, 0, 1, 8, 28, 86, 320, 1476, 8338, 50620, 269889, 0, 1, 9, 36, 119, 456, 2151, 12634, 84714, 593347, 3567412, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 04 2025

Keywords

Examples

			Square array begins:
  1,    1,    1,    1,     1,     1,     1, ...
  0,    1,    2,    3,     4,     5,     6, ...
  0,    1,    3,    6,    10,    15,    21, ...
  0,    6,   14,   25,    40,    60,    86, ...
  0,   31,   75,  135,   215,   320,   456, ...
  0,  236,  546,  951,  1476,  2151,  3012, ...
  0, 2166, 4902, 8338, 12634, 17985, 24627, ...
		

Crossrefs

Columns k=0..1 give A000007, A384575.

Programs

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

Formula

A(n,0) = 0^n; A(n,k) = k * Sum_{j=0..n} binomial(5*n-5*j+k,j)/(5*n-5*j+k) * A(n-j,j).

A384576 G.f. A(x) satisfies A(x) = ( 1 + x * A(x*A(x))^(1/2) )^2.

Original entry on oeis.org

1, 2, 3, 8, 27, 118, 609, 3602, 23866, 174186, 1383868, 11860702, 108889022, 1064691402, 11034753421, 120739899232, 1389891203976, 16781698952902, 211959646629376, 2793804347189762, 38347179124969391, 547046497259184494, 8096627908313404104
Offset: 0

Views

Author

Seiichi Manyama, Jun 04 2025

Keywords

Crossrefs

Column k=2 of A384580.
Cf. A143500.

Programs

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

Formula

See A384580.
G.f.: B(x)^2, where B(x) is the g.f. of A143500.
Showing 1-4 of 4 results.