707480

Appears in sequences

• Number of n X n circulant singular (0,1) matrices over the reals.at n=21A086328
• a(n) is the number of configurations of n indistinguishable pairs placed on the vertices of the ladder graph P_2 X P_n such that only one such pair is joined by an edge.at n=7A318244
• Triangle read by rows giving the number of configurations of n indistinguishable pairs placed on the vertices of the ladder graph P_2 X P_n such that exactly k such pairs are joined by an edge.at n=37A325753