64568

Appears in sequences

• Number of 3-covers of an unlabeled n-set.at n=20A055195
• Numbers k such that 7*R_k - 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=15A099420
• Number of (n+1)X2 0..5 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.at n=2A203710
• Number of (n+1)X4 0..5 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.at n=0A203712
• T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.at n=3A203714
• T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.at n=5A203714
• Diagonal of rational function 1/(1 - (1 + x*y) * (x^3 + y^3)).at n=19A361727