login
Number of 4n X 4n quarter-turn symmetric alternating-sign matrices (QTSASM's).
2

%I #8 Jan 17 2021 11:16:18

%S 1,2,40,6860,9779616,114640611228,10995014015567296,

%T 8604220484134405095680,54849585336544518476372715520,

%U 2845241019832977820277705514596768000,1200139922362764777157943140382976769515000000

%N Number of 4n X 4n quarter-turn symmetric alternating-sign matrices (QTSASM's).

%H G. Kuperberg, <a href="https://arxiv.org/abs/math/0008184">Symmetry classes of alternating-sign matrices under one roof</a>, arXiv:math/0008184 [math.CO], 2000-2001.

%F a(n) = A059475(n)*A005130(n)^2.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Feb 04 2001