A186401 Numbers k such that there are 9 primes between 100*k and 100*k + 99.

41, 43, 70, 73, 83, 89, 99, 115, 117, 120, 123, 128, 132, 138, 143, 150, 158, 161, 163, 168, 171, 172, 193, 200, 202, 208, 209, 216, 222, 223, 225, 229, 233, 237, 239, 246, 276, 278, 282, 288, 290, 294, 300, 302, 303, 304

Offset: 1

Author

Tim Johannes Ohrtmann, Feb 20 2011

Keywords

• nonn

Comments

There are 11555200 possible prime patterns for centuries having 9 primes. - Tim Johannes Ohrtmann, Aug 27 2015

Examples

			41 is in this sequence because there are 9 primes between 4100 and 4199 (4111, 4127, 4129, 4133, 4139, 4153, 4157, 4159 and 4177).
		

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000

Crossrefs

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

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

Programs

Mathematica

Select[Range[350],PrimePi[100#+99]-PrimePi[100#]==9&] (* Harvey P. Dale, Sep 05 2023 *)

PARI

for(n=1, 1e6, if(sum(k=100*n, 100*(n+1), ispseudoprime(k))==9, print1(n", "))); \\ Charles R Greathouse IV, Feb 21 2011

PARI

N=100; s=0; forprime(p=2, 1e6, if(p>N, if(s==9, print1((N\100)-1, ", ")); s=1; N=100*(p\100+1), s++)) \\ Charles R Greathouse IV, Feb 21 2011