It’s not that Jaylen Brown couldn’t miss last night. It’s just, except for once, he didn’t. Six times he fired away from beyond the 3-point arc, and five times he found the strings. There was also a 20-foot pull-up and a rather thunderous driving dunk. When Brown left late in the third quarter with a banged-up knee that he says is not serious, the 6-foot-7 wing had produced 22 points in 25 minutes. And while he was available to return, he and most of the Celtics regulars took the last period of the 113-86 thrashing of the Sacramento Kings off. “Just working on it,” Brown said of his long-distance prowess. “Just not really thinking about it. Just letting it fly. My teammates found me, and Kyrie (Irving) did a good job of hitting me and hitting me in rhythm, and some of them just happened to go in tonight.” Just eight games into the season, the numbers suggest that, for Brown, home is where the heat is. He’s made 28 of his 46 shots at the Garden (60.9 percent), including 11-of-18 (61.1 percent) on treys. Away from the parquet, however, he’s made 18-of-53 (34 percent) and 5-of-21 (23.8), respectively. “It happens,” said Brown, who made 3-of-17 shots on the recent two-game swing to Milwaukee and Miami. “That’s the NBA. You know, you play tough games. Shots don’t fall, but you’ve got to keep your confidence and let them fly just as if they just went in. So that’s the same thing all our guys tell me and the same thing I tell all my guys. Keep your confidence and have a short-term memory. The next game is different.” There is reason to believe he is, at the moment, a victim of small sample size. Last season he actually shot better on the road, 48.8 percent to 42.3 percent. And the spread on 3-pointers was 40.7 to 28.9.