1X2X3X4+1=25=5²;2x3x4x5x6+1=121=11²;3x4x5x6x7+1=361=19²;.

问题描述:

1X2X3X4+1=25=5²;2x3x4x5x6+1=121=11²;3x4x5x6x7+1=361=19²;.
则(n+1)(n+2)(n+3)(n+4)+1=()

(n²+5n+5)²