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A339049
a(n) = A000010(2*n + 1)/A053447(n), for n >= 0.
1
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.
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
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Dec 13 2020
STATUS
approved