43968

Appears in sequences

• Number of commutative groupoids with n elements.at n=4A001425
• a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026747.at n=14A026755
• a(n) is the number of distinct (modulo geometric D3-operations) patterns which can be formed by an equilateral triangular arrangement of closely packed black and white cells satisfying the local matching rule of Pascal's triangle modulo 2, where n is the number of cells in each edge of the arrangement. The matching rule is such that any elementary top-down triangle of three neighboring cells in the arrangement contains either one or three white cells.at n=17A060553
• Coefficient triangle of polynomials (falling powers) related to convolutions of A002605(n), n>=0, (generalized (2,2)-Fibonacci). Companion triangle is A073403.at n=9A073404
• Coefficient triangle of polynomials (rising powers) related to convolutions of A002605(n), n>=0, (generalized (2,2)-Fibonacci). Companion triangle is A073405.at n=6A073406
• Number of n-element groupoids with an identity.at n=3A090601
• Least magic constant of magic squares using Smith numbers.at n=12A170928
• Values of a in A216515.at n=4A249514
• Triangular array read by rows: T(n,k) is the number of simple labeled graphs on n nodes whose maximal connected component has at most k nodes, n>=1, 1<=k<=n.at n=25A275364
• Numbers n such that the number of partitions of n(n+1)/2 (=A000041(A000217(n))) is prime.at n=4A285088
• Table read by downward antidiagonals: T(n,k) is the number of tilings of the n X k cylinder up to 180-degree rotation by two tiles that are each fixed under 180-degree rotation.at n=30A368262
• Table read by downward antidiagonals: T(n,k) is the number of tilings of the n X k cylinder up to 180-degree rotation by an asymmetric tile.at n=30A368263
• Triangle read by rows: T(n,k) is the number of nonisomorphic magmas with n elements whose center contains k elements.at n=14A391155
• 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=14A391161