124271domain: NAppears in sequencesNumber of regions in regular n-gon with all diagonals drawn.at n=42A007678Integers of the form 8k + 7 that can be written as a sum of four distinct squares of the form m, m + 1, m + 3, m + 5, where m == 2 (mod 4).at n=43A243580a(n) = A007678(2*n+1).at n=21A341735