Random Numbers (あてずっぽナンバーズ Atezuppo Numbers) is a short story featuring the SOS Brigade.
To celebrate the tenth anniversary of The Melancholy of Haruhi Suzumiya franchise, Kadokawa published the second artbook by Noizi Ito, Haruhi Hyakka (ハルヒ百花 Haruhi Many Kinds of Flowers). This included Random Numbers.
They were supposed to meet the three female members of the SOS Brigade at the shrine, and Kyon feared he would be last as usual (for which he was usually made to pay a financial penalty). He in fact suggest Koizumi deliberately arrive later than him, but Koizumi said that wouldn't work, and he wondered if Haruhi Suzumiya was responsible for that.
The three female members were dressed in kimonos, something that had been arranged with Tsuruya the previous day. When the Brigade reunited, Haruhi determined to visit every shrine in the city. Tusurya couldn't be with them, as she was on a trip to Europe. Haruhi wanted pictures of all the girls in kimonos to pay back Tsuruya.
Koizumi commented bitterly that Kyon hadn't taken him on his time travel trip with Mikuru Asahina and Yuki Nagato the day before (when Kyon went to rescue his previous self in The Disappearance), making Koizumi feel left out.
Haruhi talked about dressing Asahina as a shrine maiden, while Nagato's eyes seemed "colder" than usual.
Kyon asked Koizumi about the number he had mentioned earlier. He wondered if it was a prime number, but Koizumi said it was three prime numbers multiplied together (two of two digits, and one of three digits). He told Kyon to guess the prime numbers before they left the shrine they were at. Koizumi said Haruhi would be able to guess the numbers easily, and that asking Nagato was "cheating".
The Brigade did traditional shrine activities. Kyon noticed Nagato anxious to read the billboards documenting the history of the shrine and deity. At some point, Kyon and Haruhi got separated from the rest of the Brigade, and the strap on one of her sandals broke, causing her to complain about bad luck and whether the local god was asleep on the job. They figured walking would just break the other strap.
The other three weren't far away, but Kyon couldn't see them. He called Koizumi, hoping to get the rest of the Brigade to meet up and divide the chore of carrying Haruhi around. Koizumi instead suggested that Kyon carry Haruhi.
Kyon carried Haruhi on his shoulders, as more comfortable methods caused Haruhi's hem to ride up. Eventually they made it to the rest of the Brigade. Koizumi said they didn't need to buy new sandals as Nagato could repair the broken one.
Haruhi said that Kyon and Koizumi were dressed too plainly for the occasion. Koizumi said he knew someone who ran a clothing shop. (Kyon was suspicious of this.) Haruhi thought she just needed the two boys' heights, weights, and waist sizes. Neither Kyon nor Koizumi wanted to give these numbers, as they were embarrassing to give out.
Nagato stared at Kyon, as he realized that the three prime numbers were probably Koizumi's clothing measurements. Kyon told her it was okay not to give him the numbers, and she erased the three numbers that she had written down on the ground.
A few days later, Kyon got a letter from Koizumi. It contained two photos. One was of the SOS Brigade after they had rented clothes for the boys. The other was a secretly taken cell phone photo of Kyon carrying Haruhi.