如何在Excel中进行隔行求和?

如何在Excel中进行隔行求和?

=SUM(INDEX(A2:A12,SEQUENCE(4,,2,3)))

行数较多时自动计算取值个数。

=LET(a,A2:A12,SUM(INDEX(a,SEQUENCE(ROUNDUP(ROWS(a)/3,0),,2,3))))