A272395 Degeneracies of entanglement witness eigenstates for n spin 5 irreducible representations.

1, 0, 1, 1, 11, 76, 671, 5916, 54131, 504316, 4779291, 45898975, 445798221, 4371237794, 43213522209, 430241859971, 4310236148075, 43417944574136, 439495074016427, 4468208369691396, 45605656313488271, 467140985042718910

Offset

0,5

Comments

The Mathematica formula for a(n) as the difference of two generalized binomial coefficients is adapted from the Appendix of the Mendonça link. - Thomas Curtright, Jul 27 2016

Links

Gheorghe Coserea, Table of n, a(n) for n = 0..401

Eliahu Cohen, Tobias Hansen, Nissan Itzhaki, From Entanglement Witness to Generalized Catalan Numbers, arXiv:1511.06623 [quant-ph], 2015.

T. L. Curtright, T. S. Van Kortryk, and C. K. Zachos, Spin Multiplicities, hal-01345527, 2016.

Vaclav Kotesovec, Recurrence (of order 6)

J. R. G. Mendonça, Exact eigenspectrum of the symmetric simple exclusion process on the complete, complete bipartite and related graphs, Journal of Physics A: Mathematical and Theoretical 46:29 (2013) 295001. arXiv:1207.4106 [cond-mat.stat-mech], 2012-2013.

Formula

a(n)=(1/Pi)*int((sin(11x)/sin(x))^n*(sin(x))^2,x,0,2Pi). - Thomas Curtright, Jun 24 2016

a(n) ~ (1/20)^(3/2)*11^n/(sqrt(Pi)*n^(3/2))(1-63/(80n)+O(1/n^2)). - Thomas Curtright, Jul 26 2016

Mathematica

a[n_]:= 2/Pi*Integrate[Sqrt[(1-t)/t]*(1024t^5-2304t^4+1792t^3-560t^2 +60t-1)^n, {t, 0, 1}] (* Thomas Curtright, Jun 24 2016 *)
a[n_]:= c[0, n, 5]-c[1, n, 5]
c[j_, n_, s_]:= Sum[(-1)^k*Binomial[n, k]*Binomial[j - (2*s + 1)*k + n + n*s - 1, j - (2*s + 1)*k + n*s], {k, 0, Floor[(j + n*s)/(2*s + 1)]}] (* Thomas Curtright, Jul 26 2016 *)
a[n_]:= mult[0, n, 5]
mult[j_, n_, s_]:=Sum[(-1)^(k+1)*Binomial[n, k]*Binomial[n*s+j-(2*s+1)*k+n- 1, n*s+j-(2*s+1)*k+1], {k, 0, Floor[(n*s+j+1)/(2*s+1)]}] (* Thomas Curtright, Jun 14 2017 *)

Prog

(PARI)
N = 22; S = 5;
M = matrix(N+1, N*numerator(S)+1);
Mget(n, j) =  { M[1 + n, 1 + j*denominator(S)] };
Mset(n, j, v) = { M[1 + n, 1 + j*denominator(S)] = v };
Minit() = {
  my(step = 1/denominator(S));
  Mset(0, 0, 1);
  for (n = 1, N, forstep (j = 0, n*S, step,
     my(acc = 0);
     for (k = abs(j-S), min(j+S, (n-1)*S), acc += Mget(n-1, k));
     Mset(n, j, acc)));
};
Minit();
vector(1 + N\denominator(S), n, Mget((n-1)*denominator(S), 0))
(PARI) c(j, n) = sum(k=0, min((j + 5*n)\11, n), (-1)^k*binomial(n, k)*binomial(j - 11*k + n + 5*n - 1, j - 11*k + n*5))
a(n)=c(0, n)-c(1, n) \\ Charles R Greathouse IV, Jul 28 2016; adapted from Curtright's Mathematica code

Crossrefs

For spin S = 1/2, 1, 3/2, 2, 5/2, 3, 7/2, 4, 9/2, 5 we get A000108, A005043, A264607, A007043, A272391, A264608, A272392, A272393, A272394, this sequence.

Sequence in context: A245561 A056914 A232032 * A305727 A218395 A208599

Adjacent sequences: A272392 A272393 A272394 * A272396 A272397 A272398

Keyword

nonn

Author

Gheorghe Coserea, Apr 28 2016

Status

approved