47013

Appears in sequences

• a(n) is largest semiprime < 2*a(n-1), with a(1) = 4.at n=15A217836
• Triangle read by rows: T(n,k) gives the number of ballot sequences of length n having exactly k descents, n>=0, 0<=k<=n.at n=82A238121
• Irregular triangle read by rows: T(n,k) gives the number of ballot sequences of length n having k descents, n>=0, 0<=k<=A083920(n-1).at n=47A238122
• Number of ballot sequences of length n having exactly four descents.at n=4A241797
• a(n) = number of steps to reach 0 when starting from k = (3^n)-1 and repeatedly applying the map that replaces k with k - (sum of digits in base-3 representation of k).at n=12A261233
• Number of set partitions of [n] such that all absolute differences between least elements of consecutive blocks are <= two.at n=10A287252