A294440 Triangle read by rows: T(n,k) (n >= 1, 1 <= k <= n) = number of normalized 2n-plets, with single or double steps, associated to trees with k edges.

1, 2, 1, 4, 6, 1, 8, 25, 12, 1, 16, 90, 85, 20, 1, 32, 301, 476, 215, 30, 1, 64, 966, 2345, 1722, 455, 42, 1, 128, 3025, 10696, 11659, 4928, 854, 56, 1, 256, 9330, 46453, 71082, 43779, 12012, 1470, 72, 1, 512, 28501, 195340, 404540, 342642, 135357, 26040, 2370, 90, 1

Offset

1,2

Links

Table of n, a(n) for n=1..55.

M. Bauer and O. Golinelli, Random incidence matrices: Moments of the spectral density, arXiv:cond-mat/0007127 [cond-mat.stat-mech], 2000-2001; J. Stat. Phys. 103, 301-307 (2001).

Example

Triangle begins:
    1;
    2,     1;
    4,     6,      1;
    8,    25,     12,      1;
   16,    90,     85,     20,      1;
   32,   301,    476,    215,     30,      1;
   64,   966,   2345,   1722,    455,     42,     1;
  128,  3025,  10696,  11659,   4928,    854,    56,    1;
  256,  9330,  46453,  71082,  43779,  12012,  1470,   72,  1;
  512, 28501, 195340, 404540, 342642, 135357, 26040, 2370, 90, 1;
  ...

Crossrefs

Sequence in context: A359670 A114192 A114656 * A346905 A075497 A158983

Adjacent sequences: A294437 A294438 A294439 * A294441 A294442 A294443

Keyword

nonn,tabl

Author

N. J. A. Sloane, Nov 20 2017

Status

approved