21548

Appears in sequences

• Number of ordered quadruples of integers from [ 1..n ] with no global factor.at n=25A015634
• a(n) = [ 2nd elementary symmetric function of {sqrt(k+1)} ], k = 1,2,...,n.at n=43A025219
• Number of regions formed inside square by diagonals and the segments joining the vertices to the points dividing the sides into n equal length segments.at n=35A108914
• Area of annuli of consecutive integer thickness.at n=18A114378
• Sum of largest parts of all partitions of n plus n. Also, total number of parts in all partitions of n plus n.at n=26A225596
• Number of (n+2) X (4+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.at n=17A258962
• Number of 2 X 2 matrices with all terms in {-n,...,0,...,n} and (sum of terms) = permanent.at n=38A280914
• Number of collinear triples in a 4 X n rectangular grid.at n=31A334706