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 A089751 a(n) = the first prime in the orbit of n under f(n) = n^2 + 1, if it exists; = 0 otherwise. 0
 2, 2, 3, 17, 5, 37, 7, 17859077 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Question: Is a(n) > 0 for all n? a(9) may be equal to 0. - Michel Marcus, May 19 2013 LINKS EXAMPLE 4 -> 4^2 + 1 = 17 (prime). So a(4) = 17. PROG (PARI) a(n) = {while(! isprime(n), n = n^2 + 1; ); return (n); } \\ Michel Marcus, May 19 2013 CROSSREFS Cf. A002522. Sequence in context: A109843 A184840 A164022 * A137909 A035796 A049009 Adjacent sequences:  A089748 A089749 A089750 * A089752 A089753 A089754 KEYWORD nonn,more AUTHOR Joseph L. Pe, Jan 08 2004 STATUS approved

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Last modified August 11 18:37 EDT 2020. Contains 336428 sequences. (Running on oeis4.)