%I #20 Aug 10 2023 15:35:35

%S 1,3,9,72,81,432,972,8721,6651,98631,99540,777411,544311,9543321,

%T 9987642,98744310,76443210,964321110,988744320,7666422111,8876444310,

%U 65433321000,99865331100,98877443211,988654432221,988876444320,9888655432221

%N 3^n with digits rearranged into nonincreasing order.

%H Paolo Xausa, <a href="/A321539/b321539.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = A004186(A000244(n)). - _Michel Marcus_, Nov 10 2022

%t A321539[n_]:=FromDigits[ReverseSort[IntegerDigits[3^n]]];Array[A321539,40,0] (* _Paolo Xausa_, Aug 10 2023 *)

%o (Python)

%o def A321539(n): return int(''.join(sorted(str(3**n),reverse=True))) # _Chai Wah Wu_, Nov 10 2022

%Y The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down).

%Y Cf. A004186.

%K nonn,base

%O 0,2

%A _N. J. A. Sloane_, Nov 19 2018