Me: 1, 4, 7, 10, 13, 16, 19.

Two: 2,5,8, 1 1, 14,17,20.

Three: 3, 6, 9, 12, 15, 18

There are four different situations that can make the extracted three numbers become three integers.

Take three from the first group: c (7,3) = 35 species.

In the second group, three species were selected: c (7,3) = 35 species.

The third group takes three: c (6,3) = 20 species.

One in each group: 7×7×6=294 species.

One * * * has: 35+35+30+294=394 species.