53071

Appears in sequences

• Heptagonal numbers (A000566) that are semiprimes (A001358).at n=24A259676
• O.g.f. A(x) satisfies: [x^n] 1/(1-x)^(n^2) / exp( n*A(x) ) = 0 for n >= 1.at n=5A317342
• a(n) = Sum_{k=0..n} Stirling2(n,k) * 2^binomial(k,2).at n=6A335390