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A340408
Primes p such that p*q+q*r+r*s is prime, where q,r,s are the next primes after p.
1
3, 17, 19, 23, 43, 151, 157, 199, 229, 233, 331, 347, 461, 467, 491, 503, 523, 547, 563, 613, 617, 619, 653, 739, 743, 773, 941, 1021, 1031, 1051, 1063, 1097, 1103, 1117, 1163, 1193, 1237, 1259, 1279, 1373, 1429, 1489, 1523, 1553, 1601, 1609, 1613, 1627, 1663, 1709, 1733, 1907, 1999, 2011, 2087
OFFSET
1,1
LINKS
EXAMPLE
a(3) = 19 is a term because 19*23+23*29+29*31 = 2003 is prime.
MAPLE
q:= 2: r:= 3: s:= 5:
count:= 0: R:= NULL:
while count < 100 do
p:= q; q:= r; r:= s; s:= nextprime(s);
if isprime(p*q+q*r+r*s) then count:= count+1; R:= R, p; fi
od:
R;
PROG
(Python)
from sympy import isprime, nextprime
def aupton(terms):
p, q, r, s, alst = 2, 3, 5, 7, []
while len(alst) < terms:
if isprime(p*q + q*r + r*s): alst.append(p)
p, q, r, s = q, r, s, nextprime(s)
return alst
print(aupton(55)) # Michael S. Branicky, Mar 17 2021
CROSSREFS
Cf. A287653.
Sequence in context: A038886 A377176 A019342 * A339544 A029473 A103088
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Jan 06 2021
STATUS
approved