A293044 Number of even permutations s of {1,2,...,n} such that |s(i)-i| > 1 for each i=1,2,...,n.

1, 0, 0, 0, 1, 2, 14, 104, 854, 7850, 79870, 890348, 10799871, 141647372, 1997815108, 30156348224, 485117044079, 8285798537070, 149759338727580, 2855791585334780, 57300933786123530, 1206811729692494146, 26619251746350630604, 613691499376088985144

Offset

0,6

Links

Table of n, a(n) for n=0..23.

Dmitry Efimov, Determinants of generalized binary band matrices, arXiv:1702.05655 [math.RA], 2017.

Formula

a(n) = (A001883(n) + d(n))/2, where d(n) = (3-n)/3 if n = 0 mod 3, d(n) = (n-1)/3 if n = 1 mod 3, d(n) = 0 if n = 2 mod 3.

Crossrefs

Cf. A001883, A293045.

Sequence in context: A295865 A355069 A378611 * A343818 A160780 A279737

Adjacent sequences: A293041 A293042 A293043 * A293045 A293046 A293047

Keyword

nonn

Author

Eric M. Schmidt, Oct 09 2017

Status

approved