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A013699 Degree of variety K_{2,n}^2. 4

%I

%S 1,32,610,9842,147798,2145600,30664890,435668420,6186432967,

%T 88066807556,1258885297696,18084694597452,261164661944060,

%U 3791317346771584,55316720239735242,810944384733610356

%N Degree of variety K_{2,n}^2.

%C Number of Catalan paths (nonnegative, starting and ending at 0, step +/-1) of 4n+4 steps with all values less than or equal to n+1 (see A080934).

%H M. S. Ravi et al., <a href="http://www.nd.edu/~rosen/Paper/degree.ps">Dynamic pole assignment and Schubert calculus</a>, SIAM J. Control Optimization, 34 (1996), 813-832, esp. p. 825.

%o (PARI) K(n,q=2)=(2*n+n*q+2*q)!*sum(j=0,q,((q-2*j)*(n+2)+1)/(n+j*(n+2))!/(n+1+(q-j)*(n+2))!)

%Y Cf. A013698 (q=1), A013700 (q=3), A013701 (q=4), A013702 (q=5).

%K nonn,easy

%O 1,2

%A Joachim.Rosenthal(AT)nd.edu (Joachim Rosenthal)

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Last modified July 6 23:56 EDT 2020. Contains 335484 sequences. (Running on oeis4.)