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

Author

N. J. A. Sloane, Sep 20 2009

Keywords

• nonn
• tabl

Examples

			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;
		

Links

• 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.

Crossrefs

Cf. A152086, A102699.