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A367970 Least k such that 5*n*k+1 is a prime. 1
2, 1, 2, 2, 4, 1, 2, 1, 4, 2, 6, 1, 2, 1, 2, 3, 12, 2, 2, 1, 2, 3, 4, 2, 2, 1, 2, 2, 10, 1, 2, 4, 2, 6, 4, 1, 8, 1, 6, 2, 4, 1, 2, 3, 8, 2, 4, 1, 2, 1, 4, 2, 4, 1, 12, 1, 2, 5, 4, 2, 6, 1, 2, 2, 4, 1, 6, 3, 2, 2, 6, 5, 18, 4, 2, 2, 6, 3, 6, 1, 2, 2, 28, 1, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
A367970 = {};
Do[k=1; While[!PrimeQ[5 n k+1], k++]; AppendTo[A367970 , k], {n, 85}];
PROG
(PARI) a(n) = my(k=1); while (!isprime(5*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023
CROSSREFS
A070849 lists the corresponding primes.
Sequence in context: A255723 A309022 A214718 * A345161 A321319 A048896
KEYWORD
nonn
AUTHOR
Robert Price, Dec 17 2023
STATUS
approved

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Last modified August 5 19:23 EDT 2024. Contains 374954 sequences. (Running on oeis4.)