185283

Appears in sequences

• G.f.: exp( Sum_{n>=0} [ Sum_{k=0..n} C(n,k)^2*x^k ]^2* x^n/n ).at n=11A180718
• Number of 2 X 2 matrices having all terms in {1,...,n} and determinant = 1 (mod 3).at n=27A211071