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%I #11 May 02 2024 09:46:57
%S 4,8,30,25,57,16,27,192,132,121,185,169,465,32,306,289,489,361,451,
%T 2250,552,529,125,1586,81,1652,985,841,1057,64,1285,86166,2555,1332,
%U 1387,1369,4752,3240,2005,1681,2649,1849,2047,5456,2256,2209,343,5050,2761,5876,2862,2809,3097,15512
%N The smallest composite number k such that the digits of k and its prime factors, both written in base n, contain the same set of distinct digits.
%H Scott R. Shannon, <a href="/A372384/b372384.txt">Table of n, a(n) for n = 2..404</a>
%F a(n) = 2*n + 2 if n = 2^k - 1 with k >= 2, otherwise a(n) = n^2 if n is prime.
%e a(4) = 30 as 30 = 2 * 3 * 5 = 132_4 = 2_4 * 3_4 * 11_4, and both 132_4 and its primes factors contain the same distinct digits 1, 2, and 3.
%e a(10) = 132 as 132 = 2 * 3 * 11, and both 132 and its primes factors contain the same distinct digits 1, 2, and 3. See also A035141.
%e a(14) = 465 as 465 = 3 * 5 * 31 = 253_14 = 3_14 * 5_14 * 23_14, and both 253_14 and its primes factors contain the same distinct digits 2, 3, and 5.
%Y Cf. A027746, A035141, A035140, A372309, A371695, A000668.
%K nonn,base
%O 2,1
%A _Scott R. Shannon_, Apr 29 2024