A138176 Hankel transform of A138175.
1, -4, 144, -43264, 106832896, -2155963622400, 354617391605760000, -474686810341051524710400, 5166329306435680284163452174336, -456900249341808231214942590547243565056
Offset: 0
Links
- A. V. Razumov and Yu. G. Stroganov, On refined enumerations of some symmetry classes of alternating sign matrices, arXiv:math-ph/0312071, 2003.
Formula
sqrt(abs(a(n)))/2^n = A005156(n).
a(n) = (-1)^n*(Product_{k=1..n} (6*k-2)!*(2*k-1)!/((4*k-1)!*(4*k-2)!))^2.
Comments