How do you simplify this?

n^2(n+1)^2/4+4(n+1)^3/4  =

[ (n + 1)^2 [ n^2  + 4(n + 1) ] / 4

[ (n + 1)^2 [ n^2   + 4 n  + 4] / 4  =

[ (n + 1)^2  [  n + 2] ^2  / 4

n²(n + 1)² / 4 + 4(n + 1)³ / 4

n²(n + 1)² / 4 = n²(n² + 2n + 1) / 4 = (n⁴ + 2n³ + n²) / 4

4(n + 1)³ / 4= n³ + 3n² + 3n + 1

n⁴ + 2n³ + n² + 4n³ + 12n² + 12n + 4 = (n⁴ + 6n³ + 13n² + 12n + 4) / 4