# A074000 (b-file synthesized from sequence entry) 1 1 2 1 3 3 4 9 5 21 6 99 7 225 8 729 9 2187 10 6561 11 19845 12 58563 13 177633 14 531441 15 1594323 16 4782969 17 14344533 18 43059843 19 129127041 20 387420489 21 1162261467