The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A255730 Numbers n such that n^n - (n-1)^n + n is prime. 0
 1, 2, 4, 16, 52, 80 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(6) corresponds to a prime having 153 digits. If it exists, a(7) > 5000. n does not have the form 20k+2 (which leads to a multiple of 5) or 42k+26 (which leads to a multiple of 7). LINKS Table of n, a(n) for n=1..6. EXAMPLE 4 is in the sequence because 4^4 - 3^4 + 4 = 179 is prime. MATHEMATICA Select[Range[1000], PrimeQ[#^# - (# - 1)^# + #] &] PROG (Magma) [n: n in [0..500] |IsPrime(n^n - (n-1)^n + n)]; (PARI) is(n)=ispseudoprime(n^n-(n-1)^n+n) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A085682. Sequence in context: A104354 A153948 A284730 * A363441 A010362 A262164 Adjacent sequences: A255727 A255728 A255729 * A255731 A255732 A255733 KEYWORD nonn,more AUTHOR Vincenzo Librandi, Mar 13 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 22 10:51 EDT 2024. Contains 371897 sequences. (Running on oeis4.)