We have, 24n+4−15n−16=24(n+1)−15n−16 =16n+1−15n−16=(1+15)n+1−15n−16 =n+1C0150+n+1C2151+n+1C2152+n+1C3153+... +n+1Cn+1(15)n+1−15n−16 =1+15n+15+n+1C2152+n+1C3153+... +n+1Cn+1(15)n+1−15n−16 =152[n+1C2+n+1C315+...+(15)n−1]
Thus, 24n+4−15n−16 is divisible by 225.