380190domain: NAppears in sequencesa(n) = (30*n)!*(9*n)!*(5*n)!/((18*n)!*(15*n)!*(10*n)!*n!).at n=1A295454Number of compositions of 7*n-3 into parts 6 and 7.at n=19A373935a(n) = Sum_{k=0..floor(n/2)} binomial(k+2,3*n-6*k+2).at n=41A390035Expansion of 1 / ((1-x)^6 - x^7).at n=17A392547