27882

Appears in sequences

• Expansion of 1/(1+x+x^2-2*x^3).at n=23A077975
• Number of n-element binary operation tables, out of a total n^n^2 tables, that satisfy the axioms for an Average system. Not culled for isomorphism. The Average system axioms are avg(A,A)=A, avg(A,B)=avg(B,A), avg(avg(A,B),avg(C,D)) = avg(avg(A,C),avg(B,D)).at n=5A111773
• Number of partitions of n having no parts with multiplicity 6.at n=39A184641
• Least integer m > 0 with pi(m*n) = sigma(m), where sigma(m) is the sum of all positive divisors of m.at n=25A247603
• Number of decagons that can be formed with perimeter n.at n=44A288256
• Solution of the complementary equation a(n) = 3*a(n-1) + b(n-1), where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=9A295133
• Irregular triangle read by rows: T(n,k) is the number of essential graphs with n nodes and k (directed or undirected) edges (n >= 1, 0 <= k <= n*(n-1)/2).at n=30A368569