A210147 Numbers expressible as 2*p+q, p and q distinct primes.

7, 8, 9, 11, 12, 13, 15, 16, 17, 19, 21, 23, 24, 25, 27, 28, 29, 31, 33, 35, 36, 37, 39, 40, 41, 43, 45, 47, 48, 49, 51, 53, 55, 57, 59, 60, 61, 63, 64, 65, 67, 69, 71, 73, 75, 76, 77, 79, 81, 83, 84, 85, 87, 88, 89, 91, 93, 95, 96, 97, 99, 101, 103, 105, 107

Offset: 1

Author

Zak Seidov, Mar 22 2012

Keywords

• nonn

Comments

Odd terms are of the form 4+p (p odd prime), even terms are of the form 2+2*p (p odd prime). [No: the odd term 13 =4+9 is not of that form, nor 19=4+15; see A175221 for others. - R. J. Mathar, Aug 09 2019]

Examples

			7=2*2+3, 8=2+2*3, 9=2*2+5, 11=2*2+7, 12=2+2*5, 13=2*3+7=2*5+3; 19=2*3+13=2*7+5 etc.
		

Programs

Mathematica

Union[Flatten[{2#[[1]]+#[[2]],#[[1]]+2#[[2]]}&/@Subsets[Prime[Range[20]],{2}]]] (* Harvey P. Dale, Apr 01 2013 *)

PARI

list(lim)=my(v=[],u);forprime(p=2,lim\2-1,u=List();forprime(q=2,lim-2*p,if(p!=q,listput(u,2*p+q)));v=vecsort(concat(v,Vec(u)),,8));v \\ Charles R Greathouse IV, Mar 22 2012