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A352630 First of two consecutive primes p,q such that either p+2*q and (2*p+q)/5 or (p+2*q)/5 and 2*p+q are primes. 1
7, 11, 17, 19, 101, 109, 227, 229, 277, 349, 521, 743, 769, 839, 937, 983, 1151, 1373, 1427, 1609, 1721, 1823, 2039, 2081, 2267, 2273, 2843, 3373, 3433, 3779, 3821, 3847, 3967, 4217, 4517, 4583, 5417, 5531, 5669, 5779, 6197, 6577, 6701, 6761, 6883, 7537, 7669, 7727, 8467, 8609, 8837, 9173, 9281 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(3) = 17 is a term because it is prime, the next prime is 19, and (17+2*19)/5 = 11 and 2*17+19 = 53 are prime.
MAPLE
R:= NULL: q:= 2:
while q < 10000 do
p:= q; q:= nextprime(p); s:= p+2*q; t:= 2*p+q;
if (s mod 5 = 0 and isprime(s/5) and isprime(t)) or (t mod 5 = 0 and isprime(s) and isprime(t/5)) then R:= R, p;
fi
od:
R;
CROSSREFS
Cf. A181848.
Sequence in context: A309587 A339954 A260893 * A360396 A299978 A131229
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Mar 24 2022
STATUS
approved

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Last modified April 24 05:23 EDT 2024. Contains 371918 sequences. (Running on oeis4.)