 1 , 1 , 3 , 25 , 543 , 29281 , 3781503 , … ( sequence A003024 in the OEIS ) . 
 1 , 1 , 3 , 25 , 543 , 29281 , 3781503 , … ( sequence A003024 in the OEIS ) . 
1 , 1 , 3 , 25 , 543 , 29281 , 3781503 , … ( sequence A003024 in the OEIS ) .