A367970 Least k such that 5*n*k+1 is a prime.

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

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..5000

Mathematica

A367970 = {};
Do[k=1; While[!PrimeQ[5 n k+1], k++]; AppendTo[A367970 , k], {n, 85}];
A367970

Prog

(PARI) a(n) = my(k=1); while (!isprime(5*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023

Crossrefs

Cf. A016014, A024894.

A070849 lists the corresponding primes.

Sequence in context: A255723 A309022 A214718 * A345161 A321319 A048896

Adjacent sequences: A367967 A367968 A367969 * A367971 A367972 A367973

Keyword

nonn

Author

Robert Price, Dec 17 2023

Status

approved