A339049 a(n) = A000010(2*n + 1)/A053447(n), for n >= 0.

1, 2, 2, 2, 2, 2, 2, 4, 4, 2, 4, 2, 2, 2, 2, 6, 4, 4, 2, 4, 4, 6, 4, 2, 2, 8, 2, 4, 4, 2, 2, 12, 8, 2, 4, 2, 8, 4, 4, 2, 2, 2, 16, 4, 8, 12, 12, 4, 4, 4, 2, 2, 8, 2, 6, 4, 8, 4, 12, 8, 2, 8, 2, 18, 12, 2, 12, 4, 4, 2, 4, 4, 8, 4, 2, 10, 8, 12, 6

Offset

0,2

Comments

This gives the number of seeds S(2*n+1) = a(n) needed for the complete quadrupling system modulo 2*n + 1 given in A339046.

Links

Table of n, a(n) for n=0..78.

Formula

a(n) = phi(2*n + 1)/A053447(n), for n >= 0, with phi = A000010.

Mathematica

Array[EulerPhi[#]/MultiplicativeOrder[4, #] &[2 # + 1] &, 61, 0] (* Michael De Vlieger, Dec 13 2020 *)

Prog

(PARI) a(n) = eulerphi(2*n+1)/znorder(Mod(4, 2*n+1)); \\ Michel Marcus, Dec 15 2020

Crossrefs

Cf. A000010, A053447, A339046.

Sequence in context: A247869 A036263 A307378 * A279401 A168514 A326353

Adjacent sequences: A339046 A339047 A339048 * A339050 A339051 A339052

Keyword

nonn,easy

Author

Wolfdieter Lang, Dec 13 2020

Status

approved