367874

Appears in sequences

• Consider a room of size r X s where rs = 2n and 1 <= r, 1 <= s; count ways to arrange n Tatami mats in room; a(n) = total number of ways for all choices of r and s. Two arrangements are distinguished if one is a rotation or reflection of the other.at n=31A067925
• Numbers k such that p1=2k+3, p2=4k+5, p3=6k+7, p4=8k+9 and p5=10k+11 are all prime.at n=20A105654