289440

Appears in sequences

• Number of ordered pairs (a,b) of elements of the symmetric group S_n such that the pair a,b generates a proper subgroup of S_n.at n=5A086502
• a(n) = 4*3*2*1 - 8*7*6*5 + 12*11*10*9 - 16*15*14*13 + ... - (up to the n-th term).at n=30A319887
• a(n) = 9*8*7*6*5*4*3*2*1 - 18*17*16*15*14*13*12*11*10 + 27*26*25*24*23*22*21*20*19 - ... + (up to the n-th term).at n=12A319892