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.

Previous Showing 11-13 of 13 results.

A131249 A007318 * A052509.

Original entry on oeis.org

1, 2, 1, 4, 4, 1, 8, 12, 5, 1, 16, 32, 18, 6, 1, 32, 80, 57, 24, 7, 1, 64, 192, 168, 82, 31, 8, 1, 128, 448, 471, 260, 113, 39, 9, 1, 256, 1024, 1270, 790, 374, 152, 48, 10, 1
Offset: 0

Views

Author

Gary W. Adamson, Jun 23 2007

Keywords

Comments

Row sums = A061667: (1, 3, 9, 26, 73, 201, ...).

Examples

			First few rows of the triangle:
   1;
   2,  1;
   4,  4,  1;
   8, 12,  5,  1;
  16, 32, 18,  6,  1;
  32, 80, 57, 24,  7,  1;
  ...
		

Crossrefs

Formula

Binomial transform of A052509.

A131250 A007318 * A004070.

Original entry on oeis.org

1, 2, 1, 4, 4, 1, 8, 11, 6, 1, 16, 26, 22, 8, 1, 32, 57, 64, 37, 10, 1, 64, 120, 163, 130, 56, 12, 1, 128, 247, 382, 386, 232, 79, 14, 1, 256, 502, 848, 1024, 794, 378, 106, 16, 1, 512, 1013, 1816, 2510, 2380, 1471, 576, 137, 18, 1
Offset: 0

Views

Author

Gary W. Adamson, Jun 23 2007

Keywords

Comments

Row sums = A061667: (1, 3, 9, 26, 73, 201, ...).
Companion triangle = A131249 = A007318 * A052509, where A052509 is the reversal of A004070.
Reversal of A097750. - Philippe Deléham, Jan 11 2014
Riordan array (1/(1-2x), x/(1-x)^2). - Philippe Deléham, Jan 11 2014
Diagonal sums are A045623. - Philippe Deléham, Jan 11 2014

Examples

			First few rows of the triangle:
   1;
   2,  1;
   4,  4,  1;
   8, 11,  6,  1;
  16, 26, 22,  8,  1;
  32, 57, 64, 37, 10,  1;
  ...
		

Crossrefs

Formula

Binomial transform of A004070.
T(n,k) = 2*T(n-1,k) + T(n-1,k-1) - T(n-2,k), T(0,0)=1, T(n,k)=0 if k < 0 or if k > n. - Philippe Deléham, Jan 11 2014

Extensions

More terms from Philippe Deléham, Jan 11 2014

A322378 Triangle read by rows: T(n,k) is the number of nondecreasing Dyck prefixes (i.e., left factors of nondecreasing Dyck paths) of length n and final height k (0 <= k <= n).

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 0, 2, 0, 1, 2, 0, 3, 0, 1, 0, 5, 0, 4, 0, 1, 5, 0, 9, 0, 5, 0, 1, 0, 13, 0, 14, 0, 6, 0, 1, 13, 0, 26, 0, 20, 0, 7, 0, 1, 0, 34, 0, 45, 0, 27, 0, 8, 0, 1, 34, 0, 73, 0, 71, 0, 35, 0, 9, 0, 1, 0, 89, 0, 137, 0, 105, 0, 44, 0, 10, 0, 1, 89, 0, 201, 0, 234, 0, 148, 0, 54, 0, 11, 0, 1, 0, 233, 0, 402, 0, 373, 0, 201, 0, 65, 0, 12, 0, 1, 233, 0, 546, 0, 733, 0, 564, 0, 265, 0, 77, 0, 13, 0, 1, 0, 610, 0, 1149, 0, 1245, 0, 818, 0, 341, 0, 90, 0, 14, 0, 1
Offset: 0

Views

Author

Keywords

Examples

			Triangle begins:
   1;
   0,   1;
   1,   0,   1;
   0,   2,   0,   1;
   2,   0,   3,   0,   1;
   0,   5,   0,   4,   0,   1;
   5,   0,   9,   0,   5,   0,   1;
   0,  13,   0,  14,   0,   6,   0,   1;
  13,   0,  26,   0,  20,   0,   7,   0,   1;
   0,  34,   0,  45,   0,  27,   0,   8,   0,   1;
  34,   0,  73,   0,  71,   0,  35,   0,   9,   0,   1;
   0,  89,   0, 137,   0, 105,   0,  44,   0,  10,   0,   1;
  89,   0, 201,   0, 234,   0, 148,   0,  54,   0,  11,   0,   1;
   0, 233,   0, 402,   0, 373,   0, 201,   0,  65,   0,  12,   0,   1;
  ...
		

Crossrefs

Columns k=0, 1 give A001519. Column k=2 gives A061667.

Formula

Riordan array: ((1 - 2*x^2)/(1 - 3*x^2 + x^4), (x*(1-x^2))/(1 - 2*x^2)).
Previous Showing 11-13 of 13 results.