121553

Properties

Appears in sequences

• Number of irreducible quasiorders with n labeled points.at n=6A046912
• Stirling transform of Catalan numbers: a(n) = Sum_{k=0..n} Stirling2(n, k)*binomial(2*k, k) / (k+1).at n=8A064856
• Numerator of Sum_{k=1..n} 1/lambda(k), where lambda(k) is the Carmichael's lambda function.at n=36A211306
• Triangular array read by rows: T(n,k) is the number of labeled quasi-orders on [n] that are composed of exactly k irreducible components n>=0, 0<=k<=n.at n=22A335987
• Primes p where p-1 is in A328596 (reversed binary expansion is an aperiodic necklace) and the same count of numbers smaller than p-1 are found in A328596 as primes smaller than p exist.at n=8A348352
• Primes in A354975.at n=24A355009
• Prime numbersat n=11440