Make sequence number on hg export start at 1 (as documented for %n). Add test.
#!/bin/sh
hg init repo
cd repo
touch foo
hg add foo
for i in 0 1 2 3 4 5 6 7 8 9 10 11; do
echo "foo-$i" >> foo
hg ci -m "foo-$i" -d "0 0"
done
for out in "%nof%N" "%%%H" "%b-%R" "%h" "%r"; do
echo "# foo-$out.patch"
hg export -v -o "foo-$out.patch" 2:tip
done