A038609 Numbers that are the sum of 2 different primes.

5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 28, 30, 31, 32, 33, 34, 36, 38, 39, 40, 42, 43, 44, 45, 46, 48, 49, 50, 52, 54, 55, 56, 58, 60, 61, 62, 63, 64, 66, 68, 69, 70, 72, 73, 74, 75, 76, 78, 80, 81, 82, 84, 85, 86, 88, 90, 91, 92

Offset

1,1

Links

R. J. Mathar, Table of n, a(n) for n = 1..9225

Maple

isA038609 := proc(n)
    local i, p, q;
    for i from 1 do
        p := ithprime(i) ;
        if 2*p > n then
            return false;
        fi;
        q := n-p ;
        if q <= p then
            return false ;
        end if;
        if isprime(q) then
            return true;
        end if;
    end do:
end proc:
n :=1 :
for c from 1 do
    if isA038609(c) then
        printf("%d %d\n", n, c) ;
        n := n+1 ;
    end if;
end do: # R. J. Mathar, Jun 09 2014

Mathematica

max = 100;
ip = PrimePi[max];
Table[Prime[i] + Prime[j], {i, ip}, {j, i + 1, ip}] // Flatten // Union // Select[#, # <= max&]& (* Jean-François Alcover, Mar 23 2020 *)

Crossrefs

Cf. A014091, A166081 (complement).

Sequence in context: A043694 A043602 A243624 * A078892 A370090 A164374

Adjacent sequences: A038606 A038607 A038608 * A038610 A038611 A038612

Keyword

nonn

Author

Vasiliy Danilov (danilovv(AT)usa.net) 1998 Jul

Status

approved