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A371619
a(n) is the least integer m such that p#*m - 1 is prime for all primes p <= prime(n).
0
2, 2, 2, 2, 9, 9, 9, 224719, 384427, 16114470, 259959472, 13543584514, 100318016379, 100318016379
OFFSET
1,1
PROG
(PARI) isok(m, n) = for(i=1, n, my(P = vecprod(primes(i))); if (! isprime(P*m-1), return(0)); ); return(1);
a(n) = my(m=1); while (!isok(m, n), m++); m;
CROSSREFS
Cf. A002110.
Sequence in context: A353392 A360310 A085056 * A265447 A156538 A249768
KEYWORD
nonn,more
AUTHOR
Michel Marcus, Mar 29 2024
STATUS
approved