A047935 Consider primes p with least positive primitive root g such that q=p+g is next prime after p; sequence gives values of g.

1, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 6, 2, 6, 10, 2, 6, 2, 2, 2, 6, 2, 2, 6, 6, 2, 10, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6, 2, 6, 2, 6, 6, 2, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 10, 2, 2, 2, 2, 6, 2, 6, 2, 2, 2, 2, 6, 2, 2, 2, 2, 10, 6, 10, 2, 2, 2, 10, 2, 2, 2, 6, 10

Offset

1,2

References

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 864.

Links

T. D. Noe, Table of n, a(n) for n=1..1000

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

Index entries for primes by primitive root

Example

11 has primitive root 2 and 11+2 = 13 is prime after 11, which contributes a 2 to the sequence.

Mathematica

f[p_] := {g = PrimitiveRoot[p], p + g == NextPrime[p]};
A047935 = Select[f /@ Prime /@ Range[1000], #[[2]]& ][[All, 1]](* Jean-François Alcover, Feb 15 2012 *)

Crossrefs

Cf. A047933, A047934. See also A001918.

Sequence in context: A244463 A307590 A307987 * A365882 A103795 A123627

Adjacent sequences: A047932 A047933 A047934 * A047936 A047937 A047938

Keyword

nice,nonn

Author

Felice Russo

Extensions

More terms from James A. Sellers, Dec 22 1999

Status

approved