67184

Appears in sequences

• Fibonacci sequence beginning 0, 26.at n=18A022360
• a(n) = 6*(n+1)*(2*n+6)!/((n+3)!*(n+5)!).at n=8A028379
• Composite binary rooted trees with external nodes.at n=31A035102
• Expansion of (1+x*C)*C^3, where C = (1-sqrt(1-4*x))/(2*x) is g.f. for Catalan numbers, A000108.at n=9A070031
• Denominator of sum of all elements M(i,j,k) = i*j/k, (i,j,k = 1..n). a(n) = Denominator[Sum[Sum[Sum[i*j/k,{i,1,n}],{j,1,n}],{k,1,n}]].at n=20A099866
• Denominators of third-order harmonic numbers (defined by Conway and Guy, 1996).at n=19A124838
• Denominator of Sum_{k=1..n} k*H_{n+k} where H_m = Sum_{i=1..m} 1/i.at n=21A144655
• Indices of perfect polynomials over GF(2).at n=12A178909
• G.f. satisfies: A(x) = 1 + 2*x*sqrt(A(x)/A(-x)).at n=23A198786
• Expansion of Product_{k>=1} (1/(1 - 2*x^k))^k.at n=12A261561
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-1)*b(n), where a(0) = 1, a(1) = 4, b(0) = 2, b(1) = 3, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences.at n=16A296274
• Number of unlabeled rooted semi-identity trees with n nodes.at n=15A306200