43906

Appears in sequences

• a(n) = T(n,n-5), array T as in A055807.at n=26A055810
• a(n) = (3*n*F(2n-1) + (3-n)*F(2n))/5 where F() = Fibonacci numbers A000045.at n=11A059502
• G.f.: A(x) = exp( Sum_{n>=1} 2^[A001511(n)^2]*x^n/n ) where A001511(n) is the exponent in the highest power of 2 that divides 2n.at n=9A180591
• Number of 2 X 2 matrices having all terms in {1,...,n} and determinant d satisfying -n < d < n.at n=23A211070