55222

Appears in sequences

• Self-conjugate digitized partition numbers.at n=24A068325
• Lexicographically earliest sequence of increasing numbers whose digits satisfy the "Fractal Jump" rule using only the digits 2 and 5: keep the first digit "d" of the sequence, then jump over the next "d" digits and keep the digit "e" on which you have landed. Jump now over the next "e" digits and keep the digit "f" on which you have landed, etc. The succession "def..." of kept digits is the sequence itself.at n=21A105647
• Semiprimes (A001358) made of nontrivial runs of identical digits.at n=36A116063
• Triangle read by rows: T(n,k) = 3*T(n-1,k-1) + 3*T(n-1,k) - 2*T(n-2,k-1) with T(n,0) = T(n,n) = 1.at n=47A152613
• Triangle read by rows: T(n,k) = 3*T(n-1,k-1) + 3*T(n-1,k) - 2*T(n-2,k-1) with T(n,0) = T(n,n) = 1.at n=52A152613
• Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero and first and second differences in -n..n.at n=9A208974
• a(n) = Sum_{k=1..n} phi(k)*phi(k+1)*phi(k+2), where phi(k) = A000010(k) is Euler's totient function.at n=30A335131
• Table read by rows: T(n, k) is the number of permutations of size n whose incidence graph has treewidth k.at n=41A368500