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Fibonacci self-fusion matrix, by antidiagonals.
65

%I #23 Feb 18 2020 13:55:11

%S 1,1,1,2,2,2,3,3,3,3,5,5,6,5,5,8,8,9,9,8,8,13,13,15,15,15,13,13,21,21,

%T 24,24,24,24,21,21,34,34,39,39,40,39,39,34,34,55,55,63,63,64,64,63,63,

%U 55,55,89,89,102,102,104,104,104,102,102,89,89,144,144,165,165

%N Fibonacci self-fusion matrix, by antidiagonals.

%C The Fibonacci self-fusion matrix, F, is the fusion P**Q, where P and Q are the lower and upper triangular Fibonacci matrices. See A193722 for the definition of fusion of triangular arrays.

%C Every term F(n,k) of F is a product of two Fibonacci numbers; indeed,

%C F(n,k)=F(n)*F(k+1) if k is even;

%C F(n,k)=F(n+1)*F(k) if k is odd.

%C antidiagonal sums: (1,2,6,12,...), A054454

%C diagonal (1,2,6,15,...), A001654

%C diagonal (1,3,9,24,...), A064831

%C diagonal (2,5,15,39,..), A059840

%C diagonal (3,8,24,63,..), A080097

%C diagonal (5,13,39,102,...), A080143

%C diagonal (8,21,63,165,...), A080144

%C principal submatrix sums, A202462

%C All the principal submatrices are invertible, and the terms in the inverses are in {-3,-2,-1,0,1,2,3}.

%H Clark Kimberling, <a href="https://www.fq.math.ca/Papers1/52-3/Kimberling11132013.pdf">Fusion, Fission, and Factors</a>, Fib. Q., 52 (2014), 195-202.

%F Matrix product P*Q, where P, Q are the lower and upper triangular Fibonacci matrices, A202451 and A202452.

%e Northwest corner:

%e 1...1....2....3....5....8....13

%e 1...2....3....5....8...13....21

%e 2...3....6....9...15...24....39

%e 3...5....9...15...24...39....63

%e 5...8...15...24...40...64...104

%t n = 12;

%t Q = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[Fibonacci[k], {k, 1, n}]];

%t P = Transpose[Q]; F = P.Q;

%t Flatten[Table[P[[i]][[k + 1 - i]], {k, 1, n}, {i, 1, k}]] (* A202452 as a sequence *)

%t Flatten[Table[Q[[i]][[k + 1 - i]], {k, 1, n}, {i, 1, k}]] (* A202451 as a sequence *)

%t Flatten[Table[F[[i]][[k + 1 - i]], {k, 1, n}, {i, 1, k}]] (* A202453 as a sequence *)

%t TableForm[Q] (* A202451, upper tri. Fibonacci array *)

%t TableForm[P] (* A202452, lower tri. Fibonacci array *)

%t TableForm[F] (* A202453, Fibonacci fusion array *)

%t TableForm[FactorInteger[F]]

%Y Cf. A000045, A202451, A202452, A202503 (Fibonacci fission array).

%K nonn,tabl

%O 1,4

%A _Clark Kimberling_, Dec 19 2011