254429900

Appears in sequences

• Number of commutative groupoids with n elements.at n=5A001425
• Triangle read by rows: T(n,k) is the number of nonisomorphic magmas with n elements whose center contains k elements.at n=20A391155
• Triangle read by rows: T(n,k) is the number of nonisomorphic magmas with n elements and a closed center of size k.at n=20A391161