56246400domain: NAppears in sequencesNumber of aperiodic necklaces with n labeled beads of 5 colors.at n=6A032324a(0) = 1; for n > 0, a(n) = (n!*(3*n+1))/2.at n=10A066114Fourier coefficients of Eisenstein series of degree 2 and weight 4: a(n) = coefficient of the matrix [n, 1/2; 1/2, 1] with determinant n-1/4.at n=20A323990