170103

Appears in sequences

• Number of reduced words of length n in Coxeter group on 3 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.at n=17A164352
• a(n) = (n^4 + 16*n^3 + 65*n^2 + 26*n + 12)/12.at n=34A188480