0,2
G. Kuperberg, Symmetry classes of alternating-sign matrices under one roof, arXiv math.CO/0008184 [A_{UU}(4n)]
Equals A005156(n)*A059489(n).
Cf. A005156, A059488, A059493.
Sequence in context: A142927 A114351 A080927 * A106990 A128791 A041775
Adjacent sequences: A107442 A107443 A107444 * A107446 A107447 A107448
nonn,easy
Paul Zinn-Justin (pzinn(AT)lptms.u-psud.fr), May 16 2007, Jun 04 2007