A180743 Ascending sequence of numbers such that the sum of any two distinct elements (even + odd) is a prime number.

1, 2, 3, 4, 9, 10, 27, 57, 69, 70, 267, 429, 1059, 1227, 1479, 2547, 2787, 3249, 3459, 3537, 4089, 4719, 5097, 6267, 6357, 6567, 6957, 8997, 9039, 10089, 12039, 12819, 13719, 16689, 16977, 17289, 17919, 18909, 19377, 19419, 19749

Offset: 1

Author

Michel Lagneau, Jan 22 2011

Keywords

• nonn

Examples

			70 + 69 = 139 is prime ;
70 + 57 = 127 is prime ;
70 + 9 = 79 is prime ;
70 + 3 = 73 is prime ;
70 + 1 = 71 is prime.
		

Programs

Maple

with(numtheory):nn:=50: T:=array(1..nn): T[1]:=1:T[2]:=2:a:=2:a0:=1:a1:=1:for
  k from 3 to nn do:id:=0:for n from k to 20000 while(id=0) do:n1:=irem(n,2):i:=0:for
  p from 1 to a do: if n=T[p] then i:=0:else fi: x:=n+T[p]:if type(x, prime)=true
  then i:=i+1:else fi:od: if (i=a1 and n1=0) or (i=a0 and n1=1) then T[k]:=n:a0:=a0+irem(n1+1,2):a1:=a1+n1:printf(`%d,  `, n):a:=a+1:id:=1: else fi:od:od: