OFFSET
1,2
COMMENTS
Conjecture: any integer n > 701 has a decomposition into a sum n = i+j such that 6i-1, 6i+1, 6j-1, 6j+1 are twin primes.
MAPLE
b:= n-> isprime(6*n-1) and isprime(6*n+1):
a:= proc(n) option remember; local i, k, ok;
for k from 1 +`if`(n=1, 0, a(n-1)) do ok:= true;
for i to iquo(k, 2) while ok
do ok:= not(b(i) and b(k-i)) od;
if ok then return k fi
od
end:
seq(a(n), n=1..12); # Alois P. Heinz, Jun 20 2014
PROG
(PARI) l=List(); a=select(p->isprime(p-2)&&p>5, primes(2000))\6;
for(i=1, #a-1, listput(l, 2*a[i]); for(j=i+1, #a, listput(l, (a[i]+a[j]))));
print(setminus(Set(vector(l[#l]/4, i, i)), Set(l)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Lear Young, Jun 15 2014
STATUS
approved