If you are going to put the formula in T25, then try this:
<b>Sheet master</b><table border="1" cellspacing="0" style="font-family:Calibri,Arial; font-size:11pt; background-color:#ffffff; "> <colgroup><col style="font-weight:bold; width:30px; " /><col style="width:76.04px;" /><col style="width:76.04px;" /><col style="width:144.48px;" /></colgroup><tr style="background-color:#cacaca; text-align:center; font-weight:bold; font-size:8pt; "><td > </td><td >A</td><td >S</td><td >T</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >1</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >2</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >3</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >24</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >25</td><td > </td><td > </td><td >value sheet1 cell b10</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >26</td><td > </td><td > </td><td >value sheet2 cell b10</td></tr></table><br /><table style="font-family:Arial; font-size:10pt; border-style: groove ;border-color:#00ff00;background-color:#fffcf9; color:#000000; "><tr><td ><b></b></td></tr><tr><td ><table border = "1" cellspacing="0" cellpadding="2" style="font-family:Arial; font-size:9pt;"><tr style="background-color:#cacaca; font-size:10pt;"><td >Cell</td><td >Formula</td></tr><tr><td >T25</td><td >=IF(ISBLANK(INDIRECT("Sheet"&ROW()-24&"!B10")),"",INDIRECT("Sheet"&ROW()-24&"!B10"))</td></tr><tr><td >T26</td><td >=IF(ISBLANK(INDIRECT("Sheet"&ROW()-24&"!B10")),"",INDIRECT("Sheet"&ROW()-24&"!B10"))</td></tr></table></td></tr></table>
It means that ROW() gets row 25, because you are putting the formula in cell T25, but you subtract 24, then the result is 1, to complete "Sheet" & 1 = "Sheet1"