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%I #15 Sep 17 2023 17:31:59
%S 2,4,6,8,10,16,18,20,22,24,36,60,84,90,114,120,210,420
%N Even numbers n such that { n-p ; p prime, 2 < p < n/2 } contains at least twice as many primes as composites.
%C It seems that this sequence is finite, and that 420 is the largest term. [_M. F. Hasler_, Nov 11 2009]
%e 16-3=13,16-5=11.(primes:2 times) 16-7=9.(composite:1 time);
%e 24-5=19,24-7=17,24-11=13.(primes:3 times) 24-3=21.(composite:1 time);
%e 90-3=87,90-7=83,90-11=79,90-17=73,90-19-71,90-23=67,90-29=61,90-31=59,90-37=53,90-43=47.(primes:10 times) 90-5=85,90-13=77,90-41=49.(composite:3 times),..
%o (PARI) {for(n=1,1e6, my(s=0); forprime( p=3,n-1, s+=if( isprime(2*n-p), 1,-2)); s>=0 & print1(2*n","))} \\ _M. F. Hasler_, Nov 11 2009
%K nonn,fini,full
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Jun 13 2009
%E Reworded definition and initial terms added by _M. F. Hasler_, Nov 11 2009
%E Definition reworded by _Harvey P. Dale_, Sep 17 2023
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