11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?

问题描述:

11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45,计算时规律?

等差数列
(11+45)*18/2=504