A117092 Numbers n such that nextprime(2*n) > 2*nextprime(n) (here nextprime = A007918; if p is prime then nextprime(p) = p).

2, 3, 4, 5, 7, 10, 11, 12, 13, 16, 17, 19, 22, 23, 27, 28, 29, 31, 37, 40, 41, 42, 43, 45, 46, 47, 52, 53, 57, 58, 59, 60, 61, 66, 67, 70, 71, 72, 73, 79, 82, 83, 87, 88, 89, 97, 100, 101, 102, 103, 106, 107, 108, 109, 112, 113, 126, 127, 129, 130, 131, 136

Offset: 1

Author

Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 18 2006

Keywords

• easy
• nonn

Comments

Contains all primes (A000040), and the intersection of A006093 and A047845. - Robert Israel, Mar 30 2016

Examples

			nextprime(2*12)=29 and nextprime(2)*nextprime(12)=2*13 then 12 is member because 29>26.
		

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A006093, A007918, A047845.

Programs

Maple

select(t -> nextprime(2*t) > 2*nextprime(t-1),[$1..100]); # Robert Israel, Mar 30 2016

Mathematica

Select[Range@100, NextPrime[2 #] > 2 NextPrime[# - 1] &] (* Ivan Neretin, Mar 30 2016 *)

PARI

for(i=1,100,if(nextprime(2*i)
				

Extensions

Corrected by T. D. Noe, Oct 25 2006