197340

Appears in sequences

• Smaller of unitary amicable pair.at n=9A002952
• From generalized Catalan numbers.at n=7A006630
• Unitary amicable numbers.at n=17A063991
• Triangle read by rows: T(n,k) = binomial(3n+3, k)*(n-k+1)/(n+1).at n=43A064282
• Triangle read by rows of numbers of paths in a lattice satisfying certain conditions.at n=52A071948
• Triangle read by rows: T(n,k) is the number of noncrossing trees with root degree equal to k.at n=47A092276
• Inverse of Riordan array (1,x(1-x)^2), A109970.at n=58A109971
• Inverse of Riordan array (1/(1+x)^3, x/(1+x)^3).at n=37A127898
• Numbers with prime factorization pqrstu^2.at n=27A189985
• Number of quadrangulations of a hexagon having n inner faces.at n=9A242637
• a(n) = 3*binomial(n+1, 5).at n=24A253942
• Practical numbers m with m-1 and m+1 both prime, and prime(m)-1 and prime(m)+1 both practical.at n=30A257922
• List of pairs of unitary amicable numbers (m, n) with record low values of m/n.at n=6A292020
• a(n) is the smallest member of the n-th purely periodic unitary sigma aliquot cycle listed in A336216.at n=18A336219
• a(n) = period length of the sequence A020639(n^k - 1), k >= 1.at n=57A368811
• Numbers k such that binomial(k^2,k) == 0 (mod k^3).at n=34A371474