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A003571 Order of 3 mod 3n+1. 5
1, 2, 6, 4, 3, 4, 18, 5, 20, 6, 30, 16, 18, 4, 42, 11, 42, 6, 20, 28, 10, 16, 22, 12, 12, 18, 78, 8, 16, 10, 6, 23, 48, 20, 34, 52, 27, 12, 44, 29, 5, 30, 126, 12, 18, 16, 138, 35, 28, 18, 50, 30, 78, 8, 162, 41, 39, 42, 60, 88, 45, 22, 80, 36, 16, 42, 198, 100, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Muniru A Asiru, Table of n, a(n) for n = 0..5000

MAPLE

a := n -> `if`(n=0, 1, numtheory:-order(3, 3*n+1)):

seq(a(n), n = 0..68);

MATHEMATICA

Table[MultiplicativeOrder[3, 3*n + 1], {n, 0, 68}] (* Arkadiusz Wesolowski, Nov 27 2012 *)

PROG

(Sage)

def A003571(n):

    s, m, N = 0, 1, 3*n + 1

    while True:

        k = N + m

        v = valuation(k, 3)

        s += v

        m = k // 3^v

        if m == 1: break

    return s

print([A003571(n) for n in (0..68)]) # Peter Luschny, Oct 07 2017

(GAP) List([0..70], n->OrderMod(3, 3*n+1)); # Muniru A Asiru, Feb 16 2019

(PARI) a(n) = znorder(Mod(3, 3*n+1)); \\ Michel Marcus, Feb 16 2019

CROSSREFS

Cf. A002326, A003573, A217469.

Sequence in context: A061350 A046276 A283614 * A068457 A299402 A286451

Adjacent sequences:  A003568 A003569 A003570 * A003572 A003573 A003574

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(0) = 1 added by Peter Luschny, Oct 07 2017

STATUS

approved

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Last modified January 19 21:47 EST 2020. Contains 331066 sequences. (Running on oeis4.)