193710240domain: NAppears in sequencesSum of cyclic permutations of 123...n seen as number written in base n+1: ((n+1)^n-1)*(n+1)/2.at n=7A124797Expansion of 3*x*(3*x+1)*(2*x-1) / ( (1+x)*(3*x^2+1) ).at n=33A143769a(n) = 9*(3^n - 1)/2.at n=16A168569Numbers n such that 9^10 + n^2 is a square.at n=8A180973