21423

Appears in sequences

• Starting positions of strings of three 7's in the decimal expansion of Pi.at n=21A083631
• Numbers n such that (n+j) mod (2+j) = 1 for j from 0 to 5 and (n+6) mod 8 <> 1.at n=25A096024
• Number of partitions of n+6 with largest inscribed rectangle having area <= n.at n=31A218627
• Number of partitions p of n such that median(p) > mean(p).at n=51A240220
• Numbers m such that phi(m) = k*phi(m-k) for some number 1 <= k < m - 2.at n=42A266267
• Numbers whose Euler totient function is equal to the product of the number of divisors of their k first powers, for some k.at n=43A283759
• Number of lone-child-avoiding locally disjoint unlabeled rooted trees with n vertices.at n=22A331680
• Number of integer partitions of n whose run-lengths are neither weakly increasing nor weakly decreasing.at n=40A332641
• a(n) = (2*n+1)!! * Sum_{k=0..n} k/(2*k+1).at n=5A334000
• a(n) = A352682(n, n).at n=8A352684
• Triangle read by rows. T(n, k) = (n-1)*Gould(k-1) + Bell(k) for n >= 0 and k >= 1, T(n, 0) = 1.at n=44A352686