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.

A203001 Symmetric matrix based on A007598, by antidiagonals.

Original entry on oeis.org

1, 1, 1, 4, 2, 4, 9, 5, 5, 9, 25, 13, 18, 13, 25, 64, 34, 41, 41, 34, 64, 169, 89, 113, 99, 113, 89, 169, 441, 233, 290, 266, 266, 290, 233, 441, 1156, 610, 765, 689, 724, 689, 765, 610, 1156, 3025, 1597, 1997, 1811, 1866, 1866, 1811, 1997, 1597, 3025
Offset: 1

Views

Author

Clark Kimberling, Dec 27 2011

Keywords

Comments

Let s=A007598 (squared Fibonacci numbers), 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 A203001 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A203002 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Examples

			Northwest corner:
1...1...4....9....25....64
1...2...5....13...34....89
4...5...18...41...113...290
9...13..41...99...266...724
		

Crossrefs

Programs

  • Mathematica
    s[k_] := Fibonacci[k]^2;
    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}]   (* A001654 *)
    Table[m[1, j], {j, 1, 12}]      (* A007598 *)
    Table[m[2, j], {j, 1, 12}]      (* A001519 *)
    Table[m[j, j], {j, 1, 12}]      (* A005969 *)