bracket value FORMULA

A 10 +Sheet1!$A1
10 +C5
10 +C6
10 +C7
10 +C8
B 20 +Sheet1!$A2
20 +C10
20 +C11
20 +C12
20 +C13
C 30 +Sheet1!$A3
30 +C15
30 +C16
30 +C17
30 +C18


Hi Guys,

Figures above are example. Is there any formula wherein, if i drag the formula in bracket A down to bracket B,C and so on, the cell reference Sheet1!$A1 will still be in series if it will be dragged down???