Question

1,2,4,10,25,56,) A.111 B.112 C.114 D.

Answer 1

B.数列的后项减去前项依次得到1,2,6,15,31,(),此数列的后项减去前项依次得到1,4,9,16,(25)是一个基本平方数列,所以25+31+56＝ll2.