A192226 - OEIS

%I #28 Aug 26 2015 12:21:00

%S 1,28,36,96,120,121,122,123,124,125,126,146,147,148,189,190,207,208,

%T 209,210,219,220,221,222,249,250,292,302,303,304,305,306,326,327,328,

%U 329,330,346,477,478,519,520,533,534,535,536,537,538,539,540,630,672

%N Numbers n such that all integers in the interval (n-2*sqrt(sqrt(n)), n] are composite.

%C a(14432) = 191913030 is probably the last term. Any further terms must be greater than 1.5 * 10^18. - _Charles R Greathouse IV_, Jun 30 2011

%H Charles R Greathouse IV, <a href="/A192226/b192226.txt">Table of n, a(n) for n = 1..14432</a>

%t Select[Range[700],NextPrime[#-2Sqrt[Sqrt[#]]]>#&] (* _Harvey P. Dale_, Jul 27 2011 *)

%o (PARI) is(n)=for(k=0,sqrtnint(16*n-1,4),if(isprime(n-k), return(0))); 1 \\ _Charles R Greathouse IV_, Aug 26 2015

%Y Cf. A188817, A189025, A008995.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Jun 26 2011

%E a(12)-a(13) added, a(53)-a(56) corrected by _Charles R Greathouse IV_, Jun 30 2011