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 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 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 * A010362 A262164 A322940 Adjacent sequences:  A255727 A255728 A255729 * A255731 A255732 A255733 KEYWORD nonn,more AUTHOR Vincenzo Librandi, Mar 13 2015 STATUS approved

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Last modified August 24 03:51 EDT 2019. Contains 326260 sequences. (Running on oeis4.)