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.

A159974 Triangle read by rows, M * Q; M = an infinite lower triangular Toeplitz matrix with (1, 1, 2, 3, 4, 5, ...) in every column. Q = a matrix with A034943: (1, 1, 2, 5, 12, 28, ...) as the main diagonal and the rest zeros.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 2, 2, 5, 4, 3, 4, 5, 12, 5, 4, 6, 10, 12, 28, 6, 5, 8, 15, 24, 28, 65, 7, 6, 10, 20, 36, 56, 65, 151, 8, 7, 12, 25, 48, 84, 130, 151, 351, 9, 8, 14, 30, 60, 112, 195, 302, 351, 816, 10, 9, 16, 35, 72, 140, 260, 453, 702, 816, 1897
Offset: 2

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Author

Gary W. Adamson, Apr 28 2009

Keywords

Comments

Row sums = A034943 starting (1, 2, 5, 12, 28, 65, 151, 351, ...).
As a property of eigentriangles, sum of n-th row terms = rightmost term of next row.
A034943 starting (1, 2, 5, 12, 28, ...) = the INVERT transform of (1, 1, 2, 3, 4, 5, ...).

Examples

			First few rows of the triangle:
   1;
   1, 1;
   2, 1,  2;
   3, 2,  2,  5;
   4, 3,  4,  5, 12;
   5, 4,  6, 10, 12,  28;
   6, 5,  8, 15, 24,  28,  65;
   7, 6, 10, 20, 36,  56,  65, 151;
   8, 7, 12, 25, 48,  84, 130, 151, 351;
   9, 8, 14, 30, 60, 112, 195, 302, 351, 816;
  10, 9, 16, 35, 72, 140, 260, 453, 702, 816, 1897;
  ...
Example: row 6 = (4, 3, 4, 5, 12) = termwise products of (1, 1, 2, 5, 12) and (4, 3, 2, 1, 1).
		

Crossrefs

Cf. A034943.

Formula

Triangle read by rows, M * Q; M = an infinite lower triangular Toeplitz matrix with (1, 1, 2, 3, 4, 5, ...) in every column. Q = a matrix with A034943: (1, 1, 2, 5, 12, 28, ...) as the main diagonal and the rest zeros.