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Composites in base 10 that remain composite in exactly four bases b, 2 <= b <= 10, expansions interpreted as decimal numbers.
3

%I #11 Apr 09 2024 16:00:39

%S 115,2563,3523,5071,9193,10873,12223,12811,13231,15775,19111,20203,

%T 23089,25831,27007,28171,34189,39859,40033,43361,55033,57871,58813,

%U 74371,84253,89377,93043,95833,101683,117001,125359,126673,128953,131029,134527,137467,138193

%N Composites in base 10 that remain composite in exactly four bases b, 2 <= b <= 10, expansions interpreted as decimal numbers.

%H Sebastian Petzelberger, <a href="/A256354/b256354.txt">Table of n, a(n) for n = 1..10000</a>

%H Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_024.htm">PP&P Puzzle 24: Primes in several bases</a>

%Y Cf. A052026, A256350-A256356, A038537, A052027-A052033, A084482, A236356.

%K nonn,base

%O 1,1

%A _Sebastian Petzelberger_, Mar 25 2015