OFFSET
1,1
COMMENTS
Conjecture: there are no other terms.
EXAMPLE
11 is not in the sequence because 11 = 2*7 - 3 with 7, 3 and 2*7^2 - 3^2 = 89 prime.
MAPLE
M:= 10000: # to get all terms <= M
Pmax:= floor(M/(2-sqrt(2))):
Qmax:= floor(sqrt(2)*Pmax):
Q:= select(isprime, [2, seq(i, i=3..Qmax, 2)]):
P:= select(`<=`, Q, Pmax): nQ:= nops(Q):
S:= convert(select(`<=`, P, M), set):
for p in P do
for j from 1 to nQ do
q:= Q[j];
r:= 2*p^2-q^2;
if r < 2 then break fi;
s:= 2*p-q;
if s <= M and isprime(r) and isprime(s) then S:= S minus {s} fi;
od od:
S;
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Jul 05 2022
STATUS
approved