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A175090 Composites c with result 0 under iterations of {r mod (max prime p <= r)} starting at r = c.

%I A175090 #31 Jan 01 2022 18:06:16
%S A175090 9,10,15,16,21,22,25,26,28,33,34,36,39,40,45,46,49,50,52,55,56,58,63,
%T A175090 64,66,69,70,75,76,78,81,82,85,86,88,91,92,94,96,99,100,105,106,111,
%U A175090 112,115,116,118,120,122,123,124,126,129,130,133,134,136,141,142
%N A175090 Composites c with result 0 under iterations of {r mod (max prime p <= r)} starting at r = c.
%C A175090 Intersection of A002808 and A175089.
%C A175090 Composites c such that A121559(c) = 0. - _Michel Marcus_, Aug 22 2014
%H A175090 Robert Israel, <a href="/A175090/b175090.txt">Table of n, a(n) for n = 1..10000</a>
%e A175090 Iteration procedure for a(3) = 15: 15 mod 13 = 2, 2 mod 2 = 0.
%p A175090 g:= proc(x) if isprime(x) then 0 else x mod prevprime(x) fi end proc:
%p A175090 f:= proc(x) local y; y:= x; while y > 1 do y:= g(y) od; y = 0 end proc:
%p A175090 select(not(isprime) and f, [$4..200]); # _Robert Israel_, Feb 09 2015
%t A175090 Composites := Select[Range[2, 200], ! PrimeQ[#] &]; Select[Composites, PrimeQ[# - NextPrime[#, -1]] &] (* _Carlos Eduardo Olivieri_, Feb 09 2015 *)
%Y A175090 Cf. A007917 and A064722 (both for the iterations).
%K A175090 nonn
%O A175090 1,1
%A A175090 _Jaroslav Krizek_, Jan 28 2010
%E A175090 Missing term 55 inserted, more terms added, _Michel Marcus_, Aug 22 2014