A152251 Eigentriangle, row sums = A001519, odd-indexed Fibonacci numbers.
1, 1, 1, 2, 1, 2, 4, 2, 2, 5, 8, 4, 4, 5, 13, 16, 8, 8, 10, 13, 34, 32, 16, 16, 20, 26, 34, 89, 64, 32, 32, 40, 52, 68, 89, 233, 128, 64, 64, 80, 104, 136, 178, 233, 610
Offset: 1
Examples
First few rows of the triangle = 1; 1, 1; 2, 1, 2; 4, 2, 2, 5; 8, 4, 4, 5, 13; 16, 8, 8, 10, 13, 34; 32, 16, 16, 20, 26, 34, 89; 64, 32, 32, 40, 52, 68, 89, 233; 128, 64, 64, 80, 104, 136, 178, 233, 610; ... Row 4 = (8, 4, 4, 5, 13) = termwise products of (8, 4, 2, 1, 1) and (1, 1, 2, 5, 13).
Crossrefs
Cf. A001519.
Formula
Triangle read by rows, M*Q. M = an infinite lower triangular matrix with (1, 1, 2, 4, 8, 16, ...) in every column and Q = a matrix (1, 1, 2, 5, 13, 34, ...) as the main diagonal and the rest zeros.
Let M = production matrix for reversed rows of the triangle as follows:
1, 1;
1, 0, 2;
1, 0, 0, 2;
1, 0, 0, 0, 2;
1, 0, 0, 0, 0, 2;
...
Reversal of n-th row of triangle A152251 = top row terms of M^(n-1). Example: top row of M^3 = (5, 2, 2, 4). - Gary W. Adamson, Jul 07 2011
Extensions
Last term corrected by Olivier Gérard, Aug 11 2016
Comments