229836

Appears in sequences

• Number of symmetric irreducible diagrams with 2n nodes.at n=10A004300
• G.f. A(x) satisfies: x = A(x) * (1 + A(x)) * (1 - 4*A(x)).at n=6A250888
• Numbers k such that 4*10^k + 21 is prime.at n=30A276047