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Search: a355962 -id:a355962
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Primes p such that (p+2)^(p-1) == 1 (mod p^2).
+10
7
OFFSET
1,1
COMMENTS
a(3) > 107659373057 if it exists.
Primes p such that the Fermat quotient of p base 2 (A007663) is congruent to 1/2 modulo p. - Max Alekseyev, Aug 27 2023
PROG
(PARI) forprime(p=1, , if(Mod(p+2, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355960 (k=5), A355961 (k=6), A355962 (k=7), A355963 (k=8), A355964 (k=9), A355965 (k=10).
Cf. A007663.
KEYWORD
nonn,hard,more,bref
AUTHOR
Felix Fröhlich, Jul 21 2022
STATUS
approved
Primes p such that (p+5)^(p-1) == 1 (mod p^2).
+10
6
3, 23, 1574773
OFFSET
1,1
COMMENTS
Equivalently, primes p such that 5^p == p+5 (mod p^2), or Fermat quotient q_p(5) == 1/5 (mod p). - Max Alekseyev, Sep 16 2024
PROG
(PARI) forprime(p=1, , if(Mod(p+5, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355959 (k=2), A355961 (k=6), A355962 (k=7), A355963 (k=8), A355964 (k=9), A355965 (k=10).
KEYWORD
nonn,hard,more,bref
AUTHOR
Felix Fröhlich, Jul 21 2022
STATUS
approved
Primes p such that (p+6)^(p-1) == 1 (mod p^2).
+10
6
13, 47, 3803, 151051, 240727, 259933847
OFFSET
1,1
PROG
(PARI) forprime(p=1, , if(Mod(p+6, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355959 (k=2), A355960 (k=5), A355962 (k=7), A355963 (k=8), A355964 (k=9), A355965 (k=10).
KEYWORD
nonn,hard,more
AUTHOR
Felix Fröhlich, Jul 21 2022
STATUS
approved
Primes p such that (p+8)^(p-1) == 1 (mod p^2).
+10
6
1531, 7445287
OFFSET
1,1
COMMENTS
a(3) > 34294200797 if it exists.
PROG
(PARI) forprime(p=1, , if(Mod(p+8, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355959 (k=2), A355960 (k=5), A355961 (k=6), A355962 (k=7), A355964 (k=9), A355965 (k=10).
KEYWORD
nonn,hard,more,bref
AUTHOR
Felix Fröhlich, Jul 21 2022
STATUS
approved
Primes p such that (p+9)^(p-1) == 1 (mod p^2).
+10
6
13, 19, 2207, 26041, 332698495781
OFFSET
1,1
COMMENTS
a(6) > 10^13 if it exists. - Jason Yuen, May 12 2024
PROG
(PARI) forprime(p=1, , if(Mod(p+9, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355959 (k=2), A355960 (k=5), A355961 (k=6), A355962 (k=7), A355963 (k=8), A355965 (k=10).
KEYWORD
nonn,hard,more
AUTHOR
Felix Fröhlich, Jul 21 2022
EXTENSIONS
a(5) from Jason Yuen, May 12 2024
STATUS
approved
Primes p such that (p+10)^(p-1) == 1 (mod p^2).
+10
6
13, 41, 97, 809, 1151, 1657, 800011
OFFSET
1,1
COMMENTS
A computer search taking less than 3 seconds shows there are no further terms below the one millionth prime. - Harvey P. Dale, Mar 04 2024
I ran the PARI program below for 8.5 hours and it did not find any further terms. (I do not know how far it searched.) - N. J. A. Sloane, Mar 05 2024
MATHEMATICA
Select[Prime[Range[70000]], PowerMod[#+10, #-1, #^2]==1&] (* Harvey P. Dale, Mar 04 2024 *)
PROG
(PARI) forprime(p=1, , if(Mod(p+10, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
(p+k)^(p-1) == 1 (mod p^2): A355959 (k=2), A355960 (k=5), A355961 (k=6), A355962 (k=7), A355963 (k=8), A355964 (k=9).
KEYWORD
nonn,hard,more
AUTHOR
Felix Fröhlich, Jul 21 2022
STATUS
approved

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