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%I #12 Feb 24 2019 21:09:45
%S 1,4,5,6,9,12,15,17,18,19,22,25,30,35,42,51,53,54,59,60,61,64,67,68,
%T 69,72,76,77,78,81,82,83,88,89,92,104,105,106,120,132,133,134,135,136,
%U 143,144,149,150,151,152,153,154,157,161,163,164,165,166
%N Numbers k such that number of primes in the range (k-sqrt(k), k) is equal to number of primes in the range (k, k+sqrt(k)).
%p isA192360 := proc(n) plow := floor(n-sqrt(n)) ; phi := ceil(n+sqrt(n)) ; plow := numtheory[pi](n-1)-numtheory[pi](plow) ; phi := numtheory[pi] (phi-1)-numtheory[pi](n) ; plow = phi ; end proc:
%p for n from 1 to 200 do if isA192360(n) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Jul 02 2011
%o (PARI) isA192360(n)=my(s=sqrtint(n));2*primepi(n)-isprime(n)==if(n==s^2,primepi(n-s)+primepi(n+s-1),primepi(n-s-1)+primepi(n+s))
%Y Cf. A188817, A192221.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Jun 28 2011
%E 3 removed by _Charles R Greathouse IV_, Jun 29 2011
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