81091

Appears in sequences

• Numbers k such that binomial(6k, k) + 1 is prime.at n=27A125245
• Sums of antidiagonals of A223968.at n=17A223940
• A weighted sum over the rooted trees of n nodes (A214568).at n=11A262253
• Numbers k such that 18*10^k + 1 is prime.at n=24A282456
• Expansion of Product_{k>=1} 1 / (1 - 9^(k-1)*x^k).at n=6A338678