3438204

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=12A361648
• Number of alternating permutations on [2n+1] with 1 in position n+1.at n=6A362581
• Triangular array read by rows. T(n,k) is the number of alternating permutations of [2n+1] having exactly 2k elements to the left of 1, n >= 0, 0 <= k <= n.at n=24A362582