219646

Appears in sequences

• a(n) = n*(n + 1)*(2*n^2 + 2*n - 1)/6.at n=27A006324
• a(n) is the number of symmetric permutations (p(1),p(2),...,p(m)) of (1,2,...,m), m=2n or m=2n+1, with p(m+1-k) = m+1-p(k) for 1<=k<=m, such that adjacent numbers do not differ by 1. a(n) is also the number of point-symmetric arrangements of m non-attacking kings on an m X m board, with one in each row and column.at n=7A283184
• Number of integer compositions of n that are the first sums of a unique composition.at n=34A391644