81405

Appears in sequences

• Sums of 5 distinct powers of 5.at n=29A038477
• Number of times the n-th prime appears among the decimal digits of 2^(2^n) + 1, the Fermat numbers.at n=27A078671
• G.f.: A(x) = ( Sum_{n>=0} 9^n*(2*n+1) * (-x)^(n*(n+1)/2) )^(-1/3).at n=4A202438
• Triangle read by rows, 3^k*S_3(n, k) where S_m(n, k) are the Stirling-Frobenius subset numbers of order m; n >= 0, k >= 0.at n=25A225466