1*2=22*3=63*4=124*5=205*6=306*7=427*8=562,6,12,20,30,42( 56)
2,6,12,20,30,42(56 )本题是 数列 n*(n+1)
2+4=66+6=1212+8=2020+10=3030+12=4242+14=56