261240

Appears in sequences

• Theta series of A_7 lattice.at n=26A008447
• Number of length n 1..(5+2) arrays with no leading or trailing partial sum equal to a prime.at n=9A254201
• a(n) = n*((2*n + 1)*(2*n^2 + 2*n + 3) - 3*(-1)^n)/24.at n=35A325517