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 A078931 Numbers k that divide prime(k)+1 or prime(k)-1. 2
 1, 2, 3, 4, 5, 6, 10, 12, 14, 70, 72, 181, 182, 440, 1053, 6458, 6459, 6460, 6461, 6466, 6471, 40087, 40089, 100362, 251712, 251732, 251737, 251742, 637236, 637320, 637334, 637336, 1617173, 4124466, 10553445, 10553455, 10553504, 10553505, 10553547, 10553569 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..40. FORMULA Equals A023143 union A045924. a(n) = A000720(A162567(n)). - Alois P. Heinz, Feb 20 2023 EXAMPLE 181 is in the sequence because the 181st prime is 1087, and 1086 is divisible by 181 (although 1088 is not so divisible). MATHEMATICA ndpQ[n_]:=Module[{p=Prime[n]}, Divisible[p-1, n]||Divisible[p+1, n]]; Select[Range[100000], ndpQ] (* Harvey P. Dale, Apr 03 2011 *) CROSSREFS Cf. A000720, A162567. Sequence in context: A333987 A342476 A285614 * A018779 A018382 A348654 Adjacent sequences: A078928 A078929 A078930 * A078932 A078933 A078934 KEYWORD nonn AUTHOR Benoit Cloitre, Jan 12 2003 EXTENSIONS Corrected and example added by Harvey P. Dale, Apr 03 2011 Extended with terms from A023143 and A045924 by Michel Marcus, Nov 30 2013 STATUS approved

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Last modified November 28 09:06 EST 2023. Contains 367411 sequences. (Running on oeis4.)