Whisk together flour, baking powder, sugar, and 1 teaspoon salt in a medium bowl.
Cut enough kernels from cobs to measure 2 cups. Using back of a knife, scrape pulp from cobs and transfer to a blender with milk and 1/2 cup corn. Purée until smooth, then strain through a sieve into another medium bowl, pressing on and then discarding solids.
Whisk in eggs, oil, and butter.
Add to flour mixture with remaining 1 1/2 cups corn and whisk until just combined.
Heat a griddle or heavy skillet over medium heat until hot, then lightly brush with oil. Working in batches, pour 1/3 cup batter per pancake onto griddle and cook until bubbles appear on surface and undersides are golden-brown, about 2 minutes. Flip with a spatula and cook until undersides are golden-brown, about 1 minute more. (Reduce heat if pancakes brown too quickly.) Lightly oil griddle between batches if necessary.
