A202874 Symmetric matrix based on (1,2,3,5,8,13,...), by antidiagonals.

1, 2, 2, 3, 5, 3, 5, 8, 8, 5, 8, 13, 14, 13, 8, 13, 21, 23, 23, 21, 13, 21, 34, 37, 39, 37, 34, 21, 34, 55, 60, 63, 63, 60, 55, 34, 55, 89, 97, 102, 103, 102, 97, 89, 55, 89, 144, 157, 165, 167, 167, 165, 157, 144, 89, 144, 233, 254, 267, 270, 272, 270, 267, 254

Offset

1,2

Comments

Let s=(1,2,3,5,8,13,...)=(F(k+1)), where F=A000045, and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A202874 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A202875 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Links

Table of n, a(n) for n=1..64.

Example

Northwest corner:
1....2....3....5....8....13
2....5....8....13...21...34
3....8....14...23...37...60
5....13...23...39...63...102
8....21...37...63...102..167

Mathematica

s[k_] := Fibonacci[k + 1];
U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[s[k], {k, 1, 15}]];
L = Transpose[U]; M = L.U; TableForm[M]
m[i_, j_] := M[[i]][[j]];
Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]
f[n_] := Sum[m[i, n], {i, 1, n}] + Sum[m[n, j], {j, 1, n - 1}]
Table[f[n], {n, 1, 12}]
Table[Sqrt[f[n]], {n, 1, 12}]  (* A001911 *)
Table[m[1, j], {j, 1, 12}]     (* A000045 *)
Table[m[j, j], {j, 1, 12}]     (* A119996 *)
Table[m[j, j + 1], {j, 1, 12}] (* A180664 *)
Table[Sum[m[i, n + 1 - i], {i, 1, n}], {n, 1, 12}]  (* A002940 *)

Crossrefs

Cf. A202875.

Sequence in context: A316311 A317266 A067330 * A355197 A199512 A303969

Adjacent sequences: A202871 A202872 A202873 * A202875 A202876 A202877

Keyword

nonn,tabl

Author

Clark Kimberling, Dec 26 2011

Status

approved