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.

A140069 Triangle read by rows, n-th row = (n-1)-th power of the matrix X * [1,0,0,0,...]; where X = an infinite lower triangular bidiagonal matrix with [2,1,2,1,2,1,...] and [1,1,1,...] in the subdiagonal.

Original entry on oeis.org

1, 2, 1, 4, 3, 1, 8, 7, 5, 1, 16, 15, 17, 6, 1, 32, 31, 49, 23, 8, 1, 64, 63, 129, 72, 39, 9, 1, 128, 127, 321, 201, 150, 48, 11, 1, 256, 255, 769, 522, 501, 198, 70, 12, 1, 512, 511, 1793, 1291, 1524, 699, 338, 82, 14, 1, 1024, 1023, 4097, 3084, 4339, 2223, 1375, 420, 110, 15, 1
Offset: 1

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Author

Gary W. Adamson and Roger L. Bagula, May 04 2008

Keywords

Comments

Sum of n-th row terms = A001906(2n). Example: sum of 4th row terms = ( 8 + 7 + 5 + 1) = 21 = A001906(8).

Examples

			First few rows of the triangle are:
  1;
  2, 1;
  4, 3, 1;
  8, 7, 5, 1;
  16, 15, 17, 6, 1;
  32, 31, 49, 23, 8, 1;
  64, 63, 129, 72, 39, 9, 1;
  128, 127, 321, 201, 150, 48, 11, 1;
  256, 255, 769, 522, 501, 198, 70, 12, 1;
  512, 511, 1793, 1291, 1524, 699, 338, 82, 14, 1;
  1024, 1023, 4097, 3084, 4339, 2223, 1375, 420, 110, 15, 1;
  ...
		

Crossrefs

Cf. A140068.
Cf. A135225.

Formula

Triangle read by rows, n-th row = (n-1)-th power of the matrix X * [1,0,0,0,...] where X = an infinite lower triangular matrix with [1,2,1,2,1,2,...] in the main diagonal and [1,1,1,...] in the subdiagonal, with rest zeros. Perform X * [1,0,0,0,...], X * result, etc; with the result of each operation generating successive rows of the triangle.
Binomial transform of A135225, as lower triangular matrices: a(n+1,k+1) = Sum_{j=0..n} binomial(n,j)*A135225(j,k). - Gary W. Adamson, Mar 01 2012