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 A216945 Numbers k such that k-2, k^2-2, k^3-2, k^4-2 and k^5-2 are all prime. 1
 15331, 289311, 487899, 798385, 1685775, 1790991, 1885261, 1920619, 1967925, 2304805, 2479735, 3049201, 3114439, 3175039, 3692065, 4095531, 4653649, 5606349, 5708235, 6113745, 6143235, 6697425, 7028035, 7461601, 8671585, 8997121, 9260131, 10084915, 10239529 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS k^6-2 is also prime for k = 1685775, 4095531, 4653649, 5606349, 13219339, 13326069, 18439561, ... Sequence is infinite under Schinzel's Hypothesis H. a(n) >> n log^5 n. - Charles R Greathouse IV, Sep 20 2012 LINKS Table of n, a(n) for n=1..29. FORMULA Sequence is A052147 intersection A028870 intersection A038599 intersection A154831 intersection A154833. MATHEMATICA Select[Range[20000000], And@@PrimeQ/@(Table[n^i-2, {i, 1, 5}]/.n->#)&] Select[Prime[Range[680000]]+2, AllTrue[#^Range[2, 5]-2, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 11 2020 *) CROSSREFS Cf. A052147, A028870, A038599, A154831, A154833, A154935. Sequence in context: A233594 A064982 A204317 * A258572 A352477 A232382 Adjacent sequences: A216942 A216943 A216944 * A216946 A216947 A216948 KEYWORD nonn AUTHOR Michel Lagneau, Sep 20 2012 STATUS approved

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Last modified September 11 04:57 EDT 2024. Contains 375814 sequences. (Running on oeis4.)