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Numbers k such that there are 14 primes between 100*k and 100*k + 99.
1

%I #33 Mar 22 2024 03:48:08

%S 5,7,9,20,27,35,82,147,179,277,286,514,556,694,709,796,810,1158,1363,

%T 1416,2033,2173,2232,2297,2660,3054,3274,4508,4996,6635,8194,8237,

%U 11047,11467,12303,16166,19543,19882,19936

%N Numbers k such that there are 14 primes between 100*k and 100*k + 99.

%C There are 20053913 possible prime patterns for centuries having 14 primes. - _Tim Johannes Ohrtmann_, Aug 27 2015

%H T. D. Noe, <a href="/A186406/b186406.txt">Table of n, a(n) for n = 1..1000</a>

%e 5 is in this sequence because there are 14 primes between 500 and 599 (503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593 and 599).

%t Select[Range[20000],PrimePi[100#+99]-PrimePi[100#]==14&] (* _Harvey P. Dale_, Jun 20 2021 *)

%o (PARI) for(n=1, 1e6, if(sum(k=100*n,100*(n+1), ispseudoprime(k))==14, print1(n", "))); \\ _Charles R Greathouse IV_, Feb 21 2011

%o (PARI) N=100; s=0; forprime(p=2, 4e9, if(p>N, if(s==14, print1((N\100)-1,", ")); s=1; N=100*(p\100+1),s++)) \\ _Charles R Greathouse IV_, Feb 21 2011

%Y Cf. A038822 (number of primes between 100n and 100n+99), A186311 (first occurrences).

%Y Cf. A181098 (no primes), A186393-A186408 (1 to 16 primes), A186509 (17 primes), A361723 (18 primes).

%K nonn

%O 1,1

%A _Tim Johannes Ohrtmann_, Feb 20 2011

%E a(30)-a(39) from _Charles R Greathouse IV_, Feb 21 2011