33496

Appears in sequences

• Number of connected trivalent graphs with 2n nodes and with girth exactly 3.at n=9A006923
• Composite numbers k such that phi(k + d(k)) = phi(k) + d(k), where phi() = A000010(), d() = A000005().at n=24A063702
• Coefficient of x^n in the expansion of (1+x+x^3)^n.at n=12A116411
• Alternating row sums of triangle A132166 (s1(7)).at n=4A132168
• Irregular triangle C(n,g) counting connected trivalent simple graphs on 2n vertices with girth exactly g.at n=19A198303
• G.f. A(x) satisfies: A(x) = (1 - x^2*A(x)^2)/(1 - x^2*A(x)^2 - x^3*A(x)^3).at n=19A307529