A110971 Triangle T(n,k) (n >= 2, 1 <= k <= n-1) read by rows: row n gives epispectrum of a path P_n (see reference for precise definition).

1, 1, 1, 1, 2, 1, 1, 2, 4, 1, 1, 2, 6, 6, 1, 1, 2, 7, 11, 10, 1, 1, 2, 8, 14, 24, 14, 1, 1, 2, 9, 16, 35, 42, 22, 1, 1, 2, 10, 18, 45, 68, 81, 30, 1, 1, 2, 11, 20, 55, 89, 149, 138, 46, 1, 1, 2, 12, 22, 66, 110, 216, 282, 250, 62, 1, 1, 2, 13, 24, 78, 132, 285, 422, 577, 419

Offset

2,5

Links

Table of n, a(n) for n=2..77.

Toufik Mansour, Armend Sh. Shabani, Bargraphs in bargraphs, Turkish Journal of Mathematics (2018) Vol. 42, Issue 5, 2763-2773.

M. A. Michels and U. Knauer, The congruence classes of paths and cycles, Discr. Math., 309 (2009), 5352-5359.

Example

Triangle begins:
  1;
  1, 1;
  1, 2,  1;
  1, 2,  4,  1;
  1, 2,  6,  6,  1;
  1, 2,  7, 11, 10,   1;
  1, 2,  8, 14, 24,  14,   1;
  1, 2,  9, 16, 35,  42,  22,   1;
  1, 2, 10, 18, 45,  68,  81,  30,   1;
  1, 2, 11, 20, 55,  89, 149, 138,  46,    1;
  1, 2, 12, 22, 66, 110, 216, 282, 250,   62,   1;
  1, 2, 13, 24, 78, 132, 285, 422, 577,  419,  94,   1;
  1, 2, 14, 26, 91, 156, 364, 568, 945, 1070, 732, 126, 1;

Crossrefs

Cf. A152086, A102699.

Sequence in context: A137855 A113143 A181802 * A136788 A334622 A136450

Adjacent sequences: A110968 A110969 A110970 * A110972 A110973 A110974

Keyword

nonn,tabl

Author

N. J. A. Sloane, Sep 20 2009

Status

approved