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A170820 Let p = n-th prime; a(n) = (p-1)/(order of (p+3)/2 mod p). 2
2, 1, 1, 3, 1, 6, 2, 4, 1, 1, 1, 2, 2, 4, 1, 5, 2, 10, 2, 3, 1, 1, 12, 4, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 5, 2, 2, 4, 3, 42, 1, 1, 1, 1, 2, 8, 1, 1, 2, 4, 1, 1, 7, 2, 4, 6, 2, 2, 4, 30, 2, 1, 1, 1, 2, 1, 3, 2, 2, 2, 1, 25, 4, 11, 1, 10, 2, 3, 1, 1, 8, 10, 33, 1, 2, 3, 1, 6, 2, 4, 1, 2, 1, 2, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 3..65536

I. Anderson and D. A. Preece, Combinatorially fruitful properties of 3*2^(-1) and 3*2^(-2) modulo p, Discr. Math., 310 (2010), 312-324.

MAPLE

with(numtheory); [seq((ithprime(n)-1)/order((ithprime(n)+3)/2, ithprime(n)), n=3..130)];

MATHEMATICA

a[n_] := Module[{p=Prime[n]}, (p-1)/MultiplicativeOrder[(p+3)/2, p]]; Array[a, 100, 3] (* Amiram Eldar, Dec 03 2018 *)

PROG

(PARI) a(n) = my(p=prime(n)); (p-1)/znorder(Mod((p+3)/2, p)); \\ Michel Marcus, Dec 03 2018

CROSSREFS

Cf. A014664, A001917, A170821, A170822.

Sequence in context: A327981 A277606 A228267 * A339615 A003687 A104575

Adjacent sequences:  A170817 A170818 A170819 * A170821 A170822 A170823

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 24 2009

STATUS

approved

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Last modified May 9 04:06 EDT 2021. Contains 343685 sequences. (Running on oeis4.)