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A277288 Positive integers n such that n | (3^n + 5). 8
1, 2, 14, 1978, 38209, 4782974, 9581014, 244330711, 365496202, 1661392258, 116084432414, 288504187458218, 490179448388654, 802245996685561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No other terms below 10^15. Some larger terms: 79854828136468902206, 3518556634988844968631084847788071912030455376274045370172567094578. - Max Alekseyev, Oct 14 2016

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

3^14 + 5 = 4782974 = 14 * 341641, so 14 is a term.

PROG

(PARI) is(n)=Mod(3, n)^n==-5; \\ Joerg Arndt, Oct 09 2016

(Python)

A277288_list = [1, 2]+[n for n in range(3, 10**6) if pow(3, n, n)==n-5] # Chai Wah Wu, Oct 09 2016

(Sage)

def A277288_list(search_limit):

    n, t, r = 1, Integer(3), [1]

    while n < search_limit:

        n += 1

        t *= 3

        if n.divides(t+5): r.append(n)

return r # Peter Luschny, Oct 10 2016

CROSSREFS

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), this sequence (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), A277126 (k=7), A277274 (k=11).

Sequence in context: A130421 A227403 A156736 * A296412 A296410 A006266

Adjacent sequences:  A277285 A277286 A277287 * A277289 A277290 A277291

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Oct 09 2016

EXTENSIONS

a(9) from Joerg Arndt, Oct 09 2016

a(10) from Chai Wah Wu, Oct 09 2016

a(11)-a(14) from Max Alekseyev, Oct 14 2016

STATUS

approved

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Last modified July 19 09:33 EDT 2019. Contains 325155 sequences. (Running on oeis4.)