A378201 a(n) = 2*n mod q, where q is the greatest prime such that 2*n - q is also prime.

0, 0, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 19, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 13, 11, 13, 19, 3, 5, 3, 5, 7, 3, 3, 5, 7, 11, 11, 3, 3, 5, 7, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 7, 11, 11, 3, 3, 5

Offset

2,3

Links

Table of n, a(n) for n=2..99.

Mathematica

Table[Module[{p = 2, q},
  While[True, q = 2 n - p; If[PrimeQ[p] && PrimeQ[q], Break[]];
   p = NextPrime[p]]; Mod[2 n, q]], {n, 2, 100}]

Crossrefs

Cf. A002373.

Sequence in context: A206550 A284723 A190911 * A204903 A054906 A269733

Adjacent sequences: A378198 A378199 A378200 * A378202 A378203 A378204

Keyword

nonn,new

Author

Michel Eduardo Beleza Yamagishi, Nov 19 2024

Status

approved