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 A014981 a(n) = c(prime(n))/prime(n), where c = Perrin sequence A001608 (starting 0,2,3,...) and prime(n) is the n-th prime. 4
 1, 1, 1, 1, 2, 3, 7, 11, 28, 120, 197, 892, 2479, 4148, 11687, 56010, 271913, 461529, 2270882, 6599404, 11263855, 56250108, 164879269, 830987861, 7231032935, 21386730355, 36802336319, 109099442316, 187943217386 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..1000 (terms 1..200 from T. D. Noe) Ondrej Such, An Insufficient Condition for Primality, Problem 10268, Amer. Math. Monthly, Vol. 103, No. 10 (1996), p. 911. PROG (PARI) c(n) = polsym(x^3-x-1, n)[n+1]; \\ A001608 a(n) = my(p=prime(n)); c(p)/p; \\ Michel Marcus, Mar 03 2022 CROSSREFS See A001608, the main entry for the Perrin sequence. Cf. A000040, A052338, A064723. Sequence in context: A214938 A143926 A112840 * A227885 A096362 A005479 Adjacent sequences: A014978 A014979 A014980 * A014982 A014983 A014984 KEYWORD nonn,easy,nice AUTHOR Clark Kimberling, Robert G. Wilson v STATUS approved

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Last modified May 27 19:17 EDT 2023. Contains 362985 sequences. (Running on oeis4.)