1,3,7,13,21,( ),( ),( ),( ),规律是?
问题描述:
1,3,7,13,21,( ),( ),( ),( ),规律是?
答
31.43.57.73
规律就是.:1+2=3+4=7+6=13+8=21+10=31+12=43+14=57+16=73
看的懂吗?我没看错就是这样了/