[jQuery] $('#tab1 tr:gt(0)>td').filter(':nth-child(2n+1)') select also 1st td in row - aargghh

[jQuery] $('#tab1 tr:gt(0)>td').filter(':nth-child(2n+1)') select also 1st td in row - aargghh


Hi guys
this drives me crazy.
why does this also select the first td in each a row?
$('#tab1 tr:gt(0)>td').filter(':nth-child(2n+1)')
Please give me a hint :-)
Thanks a lot
Gerald