A255390 Primes of the form 173^k - 172^k.

89269, 184438202074309, 379889466040169687349246148321558634248221737128245658182879616485078366262882828905566134219669

Offset

1,1

Comments

a(4) has 1569 digits, a(5) has 2030 digits. - Vincenzo Librandi, Feb 22 2015

The values of k are 3, 7, 43, 701, 907, ... - Jinyuan Wang, May 30 2020

Links

Table of n, a(n) for n=1..3.

Michael P. May, On the Existence and Frequency Distribution of the Shell Primes, arXiv preprint arXiv:1510.01028 [math.CO], 2015.

Mathematica

Select[Table[173^n - 172^n, {n, 1000}], PrimeQ] (* Vincenzo Librandi, Feb 22 2015 *)

Prog

(Magma) [a: n in [0..200] | IsPrime(a) where a is (173^n-172^n)]; // Vincenzo Librandi, Feb 22 2015
(PARI) select(m->ispseudoprime(m), vector(100, k, 173^k-172^k)) \\ Jinyuan Wang, May 30 2020

Crossrefs

Cf. A254298.

Sequence in context: A237902 A184028 A209896 * A347076 A205290 A205898

Adjacent sequences: A255387 A255388 A255389 * A255391 A255392 A255393

Keyword

nonn

Author

Michael P. May, Feb 21 2015

Status

approved