2672670domain: NAppears in sequencesBinomial coefficient C(7n,n-9).at n=4A004377Binomial coefficients C(n,87).at n=4A017751Binomial coefficients C(91,n).at n=4A017807Doubly pentagonal numbers: a(n) = n*(3*n-2)*(3*n-1)*(3*n+1)/8.at n=30A232713Number of ways to choose 4 points in an n X n X n triangular grid.at n=10A234249