# A074188 (b-file synthesized from sequence entry) 1 1 2 4 3 8 4 25 5 121 6 729 7 5041 8 40401 9 363609 10 3629025 11 39917124 12 479040769 13 6227103744 14 87178467600 15 1307674583296 16 20922793332736 17 355687454263684 18 6402373820077225 19 121645100663836929 20 2432902009335560361