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 1-3 of 3 results.

A084861 Expansion of (1-3x+4x^2-3x^3+x^4)/(1-2x)^2.

Original entry on oeis.org

1, 1, 4, 9, 21, 48, 108, 240, 528, 1152, 2496, 5376, 11520, 24576, 52224, 110592, 233472, 491520, 1032192, 2162688, 4521984, 9437184, 19660800, 40894464, 84934656, 176160768, 364904448, 754974720, 1560281088, 3221225472
Offset: 0

Views

Author

Paul Barry, Jun 12 2003

Keywords

Comments

Partial sums give A084860. Binomial transform of signed version of A008795.

Programs

  • Mathematica
    CoefficientList[Series[(1-3x+4x^2-3x^3+x^4)/(1-2x)^2,{x,0,40}],x] (* or *) LinearRecurrence[{4,-4},{1,1,4,9,21},40] (* Harvey P. Dale, Nov 25 2020 *)

Formula

a(n) = 3(n+3)2^(n-4), n>2.

A139633 Triangle read by rows: binomial transform of a diagonalized matrix of A026741.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 3, 9, 2, 1, 4, 18, 8, 5, 1, 5, 30, 20, 25, 3, 1, 6, 45, 40, 75, 18, 7, 1, 7, 63, 70, 175, 63, 49, 4, 1, 8, 84, 112, 350, 168, 196, 32, 9, 1, 9, 108, 168, 630, 378, 588, 144, 81, 5, 1, 10, 135, 240, 1050, 756, 1470, 480, 405, 50, 11, 1, 11, 165, 330, 1650, 1386
Offset: 1

Views

Author

Gary W. Adamson and Roger L. Bagula, Apr 27 2008

Keywords

Comments

Row sums = A084860: (1, 2, 6, 15, 36, 84, 192,...).

Examples

			First few rows of the triangle are:
1;
1, 1;
1, 2, 3;
1, 3, 9, 2;
1, 4, 18, 8, 5;
1, 5, 30, 20, 25, 3;
1, 6, 45, 40, 75, 18, 7;
1, 7, 63, 70, 175, 63, 49, 4;
...
		

Crossrefs

Formula

Let X = a diagonalized matrix of A026741: [1; 0,1; 0,0,3; 0,0,0,2;], where the first few nonzero terms of A026741 are (1, 1, 3, 2, 5, 3, 7,...). The triangle = A007318 * X.

A129566 A007318 * A129565.

Original entry on oeis.org

1, 1, 1, 2, 3, 1, 4, 6, 4, 1, 8, 11, 11, 5, 1, 16, 20, 25, 16, 6, 1, 32, 37, 51, 42, 22, 7, 1, 64, 70, 98, 98, 64, 29, 8, 1, 128, 135, 183, 211, 163, 93, 37, 9, 1, 256, 264, 339, 429, 381, 256, 130, 46, 10, 1
Offset: 1

Views

Author

Gary W. Adamson, Apr 21 2007

Keywords

Comments

Row sums = A084860: (1, 2, 6, 15, 36, 84, 192, ...).

Examples

			First few rows of the triangle:
   1;
   1,  1;
   2,  3,  1;
   4,  6,  4,  1;
   8, 11, 11,  5,  1;
  16, 20, 25, 16,  6,  1;
  32, 37, 51, 42, 22,  7,  1;
  ...
		

Crossrefs

Formula

Binomial transform of A129565.
Showing 1-3 of 3 results.