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A130294
Degree of the n X n Brauer loop scheme. Also, the sum of components of the Brauer loop model in size n.
2
1, 1, 1, 3, 7, 55, 307, 6153, 82977, 4196961, 137460201, 17446527483, 1392263902567, 441865841817751, 86102618147479627, 68171466271082093265, 32487634563234662295169, 64060941478203660710291329, 74749048993664905589266454929, 366627599282115135074804792982963
OFFSET
0,4
LINKS
A. Knutson and P. Zinn-Justin, A scheme related to the Brauer loop model, Adv. in Math. 214 (2007), 40-77.
FORMULA
a(2n) = det(binomial(2i+2j+1,2i)), 0<=i,j<=n-1; a(2n+1) = det(binomial(2i+2j+3,2i+1)), 0<=i,j<=n-1.
MATHEMATICA
a[n_] := Which[n == 0, 1, n == 1, 1, EvenQ[n], Det[Table[Binomial[2i + 2j + 1, 2i], {i, 0, n/2 - 1}, {j, 0, n/2 - 1}]], True, Det[Table[Binomial[2i + 2j + 3, 2i + 1], {i, 0, (n-1)/2 - 1}, {j, 0, (n-1)/2 - 1}]]];
Table[a[n], {n, 0, 19}] (* Jean-François Alcover, Dec 14 2018 *)
CROSSREFS
Cf. A130306.
Sequence in context: A204254 A144030 A228490 * A321968 A100772 A320724
KEYWORD
nonn
AUTHOR
Paul Zinn-Justin, Aug 06 2007
EXTENSIONS
More terms from Alois P. Heinz, Dec 04 2018
STATUS
approved