A375161
Numbers k such that (23^k - 2^k)/21 is prime.
Original entry on oeis.org
5, 11, 197, 4159
Offset: 1
- J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
- P. Bourdelais, A Generalized Repunit Conjecture
- H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.
- H. Lifchitz, Mersenne and Fermat primes field
- Eric Weisstein's World of Mathematics, Repunit.
A375236
Numbers k such that (21^k - 2^k)/19 is prime.
Original entry on oeis.org
2, 3, 353, 751, 9587
Offset: 1
- P. Bourdelais, A Generalized Repunit Conjecture.
- J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
- H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.
- H. Lifchitz, Mersenne and Fermat primes field
- Eric Weisstein's World of Mathematics, Repunit.
A377031
Numbers k such that (27^k - 2^k)/25 is prime.
Original entry on oeis.org
2, 3, 269, 401, 631, 701, 1321, 2707, 5471, 6581
Offset: 1
- P. Bourdelais, A Generalized Repunit Conjecture.
- J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
- H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.
- H. Lifchitz, Mersenne and Fermat primes field
- Eric Weisstein's World of Mathematics, Repunit.
Cf.
A062587,
A062589,
A127996,
A127997,
A128344,
A204940,
A217320,
A225807,
A229542,
A375161,
A375236.
A128336
Numbers k such that (6^k + 5^k)/11 is prime.
Original entry on oeis.org
3, 5, 17, 397, 409, 643, 1783, 2617, 4583, 8783
Offset: 1
Cf.
A057171,
A082387,
A122853,
A128335,
A128337,
A128338,
A128339,
A128340,
A128341,
A128342,
A128343,
A004061,
A082182,
A121877,
A059802,
A062572,
A128344,
A128345,
A128346,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
-
k=6; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
forprime(p=3,1e4,if(ispseudoprime((6^p+5^p)/11),print1(p", "))) \\ Charles R Greathouse IV, Jul 16 2011
One more term (8783) added (unknown discoverer) corresponding to a probable prime with 6834 digits by
Jean-Louis Charton, Oct 06 2010
A128347
Numbers k such that (11^k - 5^k)/6 is prime.
Original entry on oeis.org
5, 41, 149, 229, 263, 739, 3457, 20269, 98221
Offset: 1
Cf.
A062572,
A128344,
A128345,
A128346,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354. Cf.
A004061,
A082182,
A121877,
A059802. Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128339,
A128340,
A128341,
A128342.
-
k=11; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
is(n)=isprime((11^n-5^n)/6) \\ Charles R Greathouse IV, Feb 17 2017
A128342
Numbers k such that (13^k + 5^k)/18 is prime.
Original entry on oeis.org
13, 19, 31, 359, 487, 757, 761, 1667, 2551, 3167, 6829
Offset: 1
Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128339,
A128340,
A128341,
A128343. Cf.
A004061,
A082182,
A121877,
A059802. Cf.
A062572,
A128344,
A128345,
A128346,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
-
k=13; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
is(n)=isprime((13^n+5^n)/18) \\ Charles R Greathouse IV, Feb 17 2017
A128341
Numbers k such that (12^k + 5^k)/17 is prime.
Original entry on oeis.org
3, 5, 13, 347, 977, 1091, 4861, 4967, 34679
Offset: 1
Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128339,
A128340,
A128342,
A128343.
Cf.
A062572,
A128344,
A128345,
A128346,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
-
k=12; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
Select[Range[1100],PrimeQ[(12^#+5^#)/17]&] (* Harvey P. Dale, Jul 24 2012 *)
-
is(n)=isprime((12^n+5^n)/17) \\ Charles R Greathouse IV, Feb 17 2017
A128339
Numbers k such that (9^k + 5^k)/14 is prime.
Original entry on oeis.org
3, 5, 13, 17, 43, 127, 229, 277, 6043, 11131, 11821
Offset: 1
Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128340,
A128341,
A128342,
A128343. Cf.
A004061,
A082182,
A121877,
A059802. Cf.
A062572,
A128344,
A128345,
A128346,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
-
[n: n in [3..300] |IsPrime((9^n + 5^n) div 14)]; // Vincenzo Librandi, Nov 02 2018
-
k=9; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
is(n)=isprime((9^n+5^n)/14) \\ Charles R Greathouse IV, Feb 17 2017
A128340
Numbers k such that (11^k + 5^k)/16 is prime.
Original entry on oeis.org
7, 11, 181, 421, 2297, 2797, 4129, 4139, 7151, 29033
Offset: 1
Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128339,
A128341,
A128342,
A128343.
Cf.
A062572,
A128344,
A128345,
A128346,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
-
k=11; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
is(n)=isprime((11^n+5^n)/16) \\ Charles R Greathouse IV, Feb 17 2017
A128346
Numbers k such that (9^k - 5^k)/4 is prime.
Original entry on oeis.org
3, 11, 17, 173, 839, 971, 40867, 45821, 147503
Offset: 1
Cf.
A062572,
A128344,
A128345,
A128347,
A128348,
A128349,
A128350,
A128351,
A128352,
A128353,
A128354.
Cf.
A057171,
A082387,
A122853,
A128335,
A128336,
A128337,
A128338,
A128339,
A128340,
A128341,
A128342.
-
k=9; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
-
is(n)=isprime((9^n-5^n)/4) \\ Charles R Greathouse IV, Feb 17 2017
Showing 1-10 of 66 results.
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