534888

Appears in sequences

• a(n) = 3*(2*n)!/((n+2)!*(n-1)!).at n=12A000245
• a(n) = T(n, floor(n/2)), where T = Catalan triangle (A008315).at n=23A026008
• Number of (s(0), s(1), ..., s(2n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 3, s(2n) = 3. Also T(2n,n), where T is defined in A026022.at n=11A026029
• T(n,[ n/2 ]), where T is defined in A026022.at n=22A026034
• Sum of primes dividing the repunit numbers with a prime number of digits [A031974] (with repetition).at n=4A064768
• Sum of primes dividing the repunit numbers (with repetition).at n=11A064798
• a(n) = 3*binomial(2n, n-1)/(n+2), n > 0, with a(0)=1.at n=12A071724
• Isomers of polyenes attached to benzene (see Cyvin et al. for precise definition).at n=23A121094
• Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n having k LD's (n>=0; 0<=k<=floor((n-1)/2)).at n=36A128733
• Triangle read by rows: T(n,k) = (4k+3)/(n+2k+2)*binomial(2n,n+2k+1).at n=37A158483
• Number of undirected labeled graphs on n+3 nodes with exactly n cycle graphs as connected components.at n=16A215773
• Lexicographically earliest sequence of distinct positive integers with no finite subset summing to a Catalan number (A000108).at n=32A353983
• Arises from enumeration of a certain class of partial zig-zag knight's paths on the square grid.at n=23A368379