A276671 -id:A276671 - cp's OEIS frontend

A015973 Positive integers n such that n | (3^n + 2).

1, 5, 77, 278377, 3697489, 219596687717, 56865169816619

Offset: 1

No other terms below 10^15. Some larger term: 3142423971953435020522506484187. - Max Alekseyev, Aug 04 2011

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), this sequence (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), A277126 (k=7), A277274 (k=11).

a(1)=1 prepended and a(6)-a(7) added by Max Alekseyev, Aug 04 2011

A116622 Positive integers n such that 13^n == 2 (mod n).

Original entry on oeis.org

1, 11, 140711, 863101, 1856455, 115602923, 566411084209, 706836043419179

Offset: 1

Zak Seidov, Feb 19 2006

No other terms below 10^16. - Max Alekseyev, Nov 02 2018

Cf. A116609.
Solutions to b^n == 2 (mod n): A015919 (b=2), A276671 (b=3), A130421 (b=4), A124246 (b=5), A277401 (b=7), this sequence (b=13), A333269 (b=17).
Solutions to 13^n == k (mod n): A015963 (k=-1), A116621 (k=1), this sequence (k=2), A116629 (k=3), A116630 (k=4), A116611 (k=5), A116631 (k=6), A116632 (k=7), A295532 (k=8), A116636 (k=9), A116620 (k=10), A116638 (k=11), A116639 (k=15).

Select[Range[1, 500000], Mod[13^#, #] == 2 &] (* G. C. Greubel, Nov 19 2017 *)
Join[{1}, Select[Range[5000000], PowerMod[13, #, #] == 2 &]] (* Robert Price, Apr 10 2020 *)

isok(n) = Mod(13, n)^n == 2; \\ Michel Marcus, Nov 19 2017

One more term from Ryan Propper, Jun 11 2006

Term a(1)=1 is prepended and a(7)-a(8) are added by Max Alekseyev, Jun 29 2011

A276740 Numbers n such that 3^n == 5 (mod n).

Original entry on oeis.org

1, 2, 4, 76, 418, 1102, 4687, 7637, 139183, 2543923, 1614895738, 9083990938, 23149317409, 497240757797, 4447730232523, 16000967516764, 65262766108619, 141644055557882

Offset: 1

Dmitry Ezhov, Sep 16 2016

No other terms below 10^15. Some larger terms: 194995887252090239, 2185052151122686482926861593785262. - Max Alekseyev, Oct 13 2016

			3 == 5 (mod 1), so 1 is a term;
9 == 5 (mod 2), so 2 is a term.

Cf. A066601.

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), this sequence (k=5), A277628 (k=6), A277126 (k=7), A277630 (k=8), A277274 (k=11).

Select[Range[10^7], PowerMod[3, #, #] == Mod[5, #] &] (* Michael De Vlieger, Sep 26 2016 *)

isok(n) = Mod(3, n)^n == Mod(5, n); \\ Michel Marcus, Sep 17 2016

A276740_list = [1,2,4]+[n for n in range(5,10**6) if pow(3,n,n) == 5] # Chai Wah Wu, Oct 04 2016

a(11)-a(13) from Chai Wah Wu, Oct 05 2016
a(14) from Lars Blomberg, Oct 12 2016
a(15)-a(18) from Max Alekseyev, Oct 13 2016
a(12) was missing Robert G. Wilson v, Oct 19 2016

A277126 Positive integers n such that 3^n == 7 (mod n).

Original entry on oeis.org

1, 2, 295, 883438, 252027511, 7469046275, 26782373099, 53191768475, 55246802458, 819613658855, 893727887879978

Offset: 1

Seiichi Manyama, Oct 06 2016

No other terms below 10^15. A larger term: 9135884036634915191945452485106476242. - Max Alekseyev, Oct 12 2016

Terms are not divisible by 127 (Alekseyev 2016).

			3 == 7 mod 1, so 1 is a term;
9 == 7 mod 2, so 2 is a term.

M. A. Alekseyev. "Problem 4101". Crux Mathematicorum 42:1 (2016), 28.

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), this sequence (k=7), A277274 (k=11).

isok(n) = Mod(3, n)^n == 7; \\ Michel Marcus, Oct 06 2016

a(5) from Joerg Arndt, Oct 06 2016

a(6)-a(11) from Max Alekseyev, Oct 12 2016

A277288 Positive integers k such that k divides 3^k + 5.

Original entry on oeis.org

1, 2, 14, 1978, 38209, 4782974, 9581014, 244330711, 365496202, 1661392258, 116084432414, 288504187458218, 490179448388654, 802245996685561

Offset: 1

Seiichi Manyama, Oct 09 2016

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

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

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).

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

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

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

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

A277289 Positive integers n such that n | (3^n + 7).

Original entry on oeis.org

1, 2, 4, 5, 8, 25, 44, 4664, 6568, 1353025, 2919526, 5709589, 7827725, 64661225, 85132756, 153872408, 743947534, 34304296003, 38832409867, 40263727492, 1946603375348, 2469908330348, 64471909888247, 274267749806485, 888906849689897, 896501949422459

Offset: 1

Seiichi Manyama, Oct 09 2016

nonn

No other terms below 10^15. - Max Alekseyev, Oct 14 2016

492385451091805616444 is a term.

			3^25 + 7 = 847288609450 = 25 * 33891544378, so 25 is a term.

Solutions to 3^n == k (mod n): A277340 (k=-11), this sequence (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), A277126 (k=7), A277274 (k=11).

is(n)=Mod(3,n)^n==-7; \\ Joerg Arndt, Oct 09 2016

A277289_list = [1,2,4,5]+[n for n in range(6,10**6) if pow(3,n,n)==n-7] # Chai Wah Wu, Oct 12 2016

a(17) from Joerg Arndt, Oct 09 2016
a(18)-a(20) from Chai Wah Wu, Oct 12 2016
a(21)-a(26) from Max Alekseyev, Oct 14 2016

A277274 Positive integers n such that 3^n == 11 (mod n).

Original entry on oeis.org

1, 2, 1162, 1692934, 3851999, 274422823, 14543645261, 492230729674, 773046873382, 13010754158393, 31446154470014, 583396812890467, 598371102650063

Offset: 1

Seiichi Manyama, Oct 08 2016

No other terms below 10^15. Some larger terms: 38726095838775708310162, 2682806839696008709567739369. - Max Alekseyev, Oct 12 2016

			3 == 11 mod 1, so 1 is a term.
9 == 11 mod 2, so 2 is a term.

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), A277126 (k=7), this sequence (k=11).

k = 3; lst = {1, 2}; While[k < 12000000001, If[ PowerMod[3, k, k] == 11, AppendTo[lst, k]]; k++]; lst (* Robert G. Wilson v, Oct 08 2016 *)

a(7)-a(13) from Max Alekseyev, Oct 12 2016

A277340 Positive integers n such that n | (3^n + 11).

Original entry on oeis.org

1, 2, 4, 7, 10, 92, 1099, 29530, 281473, 657892, 3313964, 9816013, 18669155396, 94849225930, 358676424226, 957439868543, 1586504109310, 41431374800470, 241469610359708, 256165266592379

Offset: 1

Seiichi Manyama, Oct 09 2016

nonn

No other terms below 10^15. Some larger terms: 9151612250553176993, 1401778935853533028413047652833, 5645122353966835994338815444821661584288016927879134, 313*(3^626+11)/6562567821545333606830 (280 digits). - Max Alekseyev, Oct 14 2016

			3^10 + 11 = 59060 = 10 * 5906, so 10 is a term.

Solutions to 3^n == k (mod n): this sequence (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), A277126 (k=7), A277274 (k=11).

is(n)=Mod(3,n)^n==-11; \\ Joerg Arndt, Oct 10 2016

A277340_list = [1,2,4,7,10]+[n for n in range(11,10**6) if pow(3,n,n)==n-11] # Chai Wah Wu, Oct 11 2016

a(13)-a(14) from Chai Wah Wu, Oct 12 2016

a(15)-a(20) from Max Alekseyev, Oct 14 2016

A277401 Positive integers n such that 7^n == 2 (mod n).

Original entry on oeis.org

1, 5, 143, 1133, 2171, 8567, 16805, 208091, 1887043, 517295383, 878436591673

Offset: 1

Seiichi Manyama, Oct 13 2016

All terms are odd.

No other terms below 10^15. Some larger terms: 181204957971619289, 21305718571846184078167, 157*(7^157-2)/1355 (132 digits). - Max Alekseyev, Oct 18 2016

			7 == 2 mod 1, so 1 is a term;
16807 == 2 mod 5, so 5 is a term.

Cf. A066438.
Cf. Solutions to 7^n == k (mod n): A277371 (k=-3), A277370 (k=-2), A015954 (k=-1), A067947 (k=1), this sequence (k=2), A277554 (k=3).
Cf. Solutions to b^n == 2 (mod n): A015919 (b=2), A276671 (b=3), A130421 (b=4), A124246 (b=5), this sequence (b=7), A116622 (b=13).

Join[{1},Select[Range[5173*10^5],PowerMod[7,#,#]==2&]] (* The program will generate the first 10 terms of the sequence; it would take a very long time to generate the 11th term. *) (* Harvey P. Dale, Apr 15 2020 *)

isok(n) = Mod(7, n)^n == 2; \\ Michel Marcus, Oct 13 2016

A066438(a(n)) = 2 for n > 1.

a(10) from Michel Marcus, Oct 13 2016

a(11) from Max Alekseyev, Oct 18 2016

A277628 Positive integers n such that 3^n == 6 (mod n).

Original entry on oeis.org

1, 3, 21, 936340943, 10460353197, 9374251222371, 23326283250291, 615790788171551

Offset: 1

Dmitry Ezhov, Oct 24 2016

No other terms below 10^15. - Max Alekseyev, Sep 12 2017

Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), A276740 (k=5), this sequence (k=6), A277126 (k=7), A277630 (k=8), A277274 (k=11).

PARI
```
isok(n) = Mod(3, n)^n == Mod(6, n);
```

a(6)-a(8) from Max Alekseyev, Sep 12 2017

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A015973 Positive integers n such that n | (3^n + 2).

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A116622 Positive integers n such that 13^n == 2 (mod n).

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A276740 Numbers n such that 3^n == 5 (mod n).

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A277126 Positive integers n such that 3^n == 7 (mod n).

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A277288 Positive integers k such that k divides 3^k + 5.

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A277289 Positive integers n such that n | (3^n + 7).

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A277274 Positive integers n such that 3^n == 11 (mod n).

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A277340 Positive integers n such that n | (3^n + 11).

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