OFFSET
1,1
COMMENTS
A076871 is the primary sequence.
EXAMPLE
8 = 4 + 4, 12 = 4 + 8, 13 = 4 + 9.
PROG
(PARI) isP(n)={
n>3 && vecmin(factor(n)[, 2])>1
};
sumset(a, b)={
my(c=vector(#a*#b));
for(i=1, #a,
for(j=1, #b,
c[(i-1)*#b+j]=a[i]+b[j]
)
);
vecsort(c, , 8)
};
upto(lim)={
my(v=select(isP, vector(floor(lim), i, i)));
select(n->n<=lim, sumset(v, v))
};
CROSSREFS
KEYWORD
nonn
AUTHOR
Charles R Greathouse IV, Jul 06 2011
STATUS
approved