21720

Appears in sequences

• Ulam's spiral (ENE spoke).at n=37A143856
• Number T(n,k) of permutations of [n] with exactly k ascents from odd to even numbers; triangle T(n,k), n>=0, 0<=k<=floor(n/2), read by rows.at n=34A231777
• Number T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape T; triangle T(n,k), n>=0, 0<=k<=max(0,floor(2*(n-1)/3)), read by rows.at n=11A247707
• Number of tilings of a 5 X n rectangle using n pentominoes of any but the T shape.at n=6A247771
• Number of (n+1)X(4+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=0A251033
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=6A251037
• Number of (1+1)X(n+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=3A251038
• Dimension of space of invariant tensors in 2n-th tensor power of third fundamental representation of Sp(8).at n=4A251594
• a(n) = 54*n^2 + 6*n.at n=20A277990
• Number of 2-dimensional closed-loop self-avoiding paths on a square lattice where each path consists of steps with incrementing length from 1 to n.at n=18A334720
• Numbers k such that A348215(k) = k.at n=35A348216
• Numbers that can be represented as p^r + q^s with 4 distinct odd primes p, q, r, s.at n=2A390179