44500

Appears in sequences

• a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026681.at n=6A026988
• Period (multiplicative order base 10) of the terms in A116074 and A116075.at n=3A116076
• Maximal number of regions obtained by a straight line drawing of the complete bipartite graph K_{n,n}.at n=20A117717
• Triangle read by rows: T(n,k) is the number of weighted lattice paths in L_n having k (1,-1)-returns to the horizontal axis. The members of L_n are paths of weight n that start at (0,0), end on the horizontal axis and whose steps are of the following four kinds: an (1,0)-step with weight 1, an (1,0)-step with weight 2, a (1,1)-step with weight 2, and a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps.at n=47A182896
• Coefficient of x in the reduction by (x^2 -> x+1) of the polynomial C(n)*x^n, where C=A022095.at n=11A192917
• a(1)=1; thereafter a(n) = (n/2)*Sum_{i=1..n-1} K(i,n-i)*a(i)*a(n-i), where K(i,j)=i/j+j/i+2.at n=4A216733
• Triangular array read by rows: T(n,k) is the number of transitive relations on {1,2,...,n} that have exactly k reflexive points, n>=0, 0<=k<=n.at n=17A245767
• Number of (n+2)X(n+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000000 or 00000001.at n=4A259634
• Number of (n+2)X(5+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000000 or 00000001.at n=4A259639
• T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000000 or 00000001.at n=40A259642
• Expansion of Product_{k>=1} 1/(1 - x^(k*(k+1)/2))^2.at n=46A298435
• Main diagonal of A332361.at n=24A332362