A256356 - OEIS

%I #16 Apr 09 2024 15:06:36

%S 33247243,64037779,104865433,130237003,238561081,550677781,947051353,

%T 1013991553,1246382791,1343122201,1607697631,1609062751,1632753601,

%U 1788658063,2203645111,2364166213,2393866411,2480419783,2518589671,2544177511,2668538575,3029334883

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

%C Are there any remaining composites in only one other base?

%H Sebastian Petzelberger, <a href="/A256356/b256356.txt">Table of n, a(n) for n = 1..150</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, A256351, A256352, A256353, A256354, A256355.

%Y Cf. A038537, A052027-A052033, A084482, A236356.

%K nonn,base,hard

%O 1,1

%A _Sebastian Petzelberger_, Mar 25 2015