650370domain: NAppears in sequencesNumber of ways to choose two points on a centered hexagonal grid of size n.at n=19A241219Triangular numbers which are products of six distinct primes.at n=11A362758Triangular numbers with tetrahedral indices: a(n) = (1/72) * (n*(n+1)*(n+2)*(n+3)*(n^2+2)).at n=18A373733