The Feast of Saint Patrick! Rather than me rewrite Wikipedia, here’s the direct link.
There are a good number of solutions to this, so it should be doable by hand.
Solutions are below the image.
SPOILER SOLUTIONS!
| SAINT_first | PATTY_second | FEAST_third |
|---|---|---|
| 14865 | 24550 | 39415 |
| 14756 | 24660 | 39416 |
| 24875 | 14550 | 39425 |
| 24657 | 14770 | 39427 |
| 26857 | 16770 | 43627 |
| 19365 | 29550 | 48915 |
| 29375 | 19550 | 48925 |
| 39276 | 19660 | 58936 |
| 37185 | 27550 | 64735 |
| 29157 | 39770 | 68927 |
| 21684 | 51440 | 73124 |
| 51496 | 21660 | 73156 |
| 48513 | 28330 | 76843 |
| 49613 | 29330 | 78943 |
| 59623 | 19330 | 78953 |
| 14538 | 64880 | 79418 |
| 72943 | 12330 | 85273 |
| 21684 | 71440 | 93124 |
| 41268 | 51880 | 93148 |
| 51278 | 41880 | 93158 |
| 37621 | 57110 | 94731 |
| 38721 | 58110 | 96831 |
| 58741 | 38110 | 96851 |
| 78543 | 18330 | 96873 |
| 78325 | 18550 | 96875 |
| 74361 | 24110 | 98471 |