450912

Appears in sequences

• Number of permutations p of [n] such that p(i), p(i+2), p(i+4),... form an up-down sequence for i in {1,2}.at n=11A361648
• Triangle read by rows: T(n, k) = (-8)^k*binomial(2*n, 2*k)*Euler(2*k, 1/2).at n=24A371637