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A079375
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Cost'{e} prime expansion of Pi^2 - 9.
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3
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2, 2, 3, 3, 5, 2, 19, 11, 29, 53, 149, 23, 7, 11, 5, 5, 3, 5, 5, 59, 11, 7, 7, 41, 19, 17, 23, 7, 5, 3, 7, 3, 11, 3, 3, 5, 2, 5, 3, 3, 53, 11, 5, 3, 41, 13, 29, 97, 13, 11, 2, 11, 5, 7, 7, 17, 5, 11, 3, 3, 7, 23, 53, 11, 5, 17, 5, 7, 3, 17
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| For x in (0,1], define P(x) = min{p: p prime, 1/x < p}, Phi(x) = P(x)x - 1. Cost'{e} prime expansion of x(0) is sequence a(0), a(1), ... given by x(n) = Phi(x(n-1)) (n>0), a(n) = P(x(n)) (n >= 0).
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LINKS
| Nathaniel Johnston, Table of n, a(n) for n = 0..5000
A. Cost'{e} [Coste], Sur un syst`{e}me fibr'{e} li'{e} a la suite des nombres premiers, Exper. Math., 11 (2002), 383-405.
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MAPLE
| Digits := 200: P := proc(x) local y; y := ceil(evalf(1/x)); if isprime(y) then y else nextprime(y); fi; end; F := proc(x) local y, i, t1; y := x; t1 := []; for i from 1 to 50 do p := P(y); t1 := [op(t1), p]; y := p*y-1; od; t1; end; F(Pi^2 - 9);
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CROSSREFS
| Cf. A079376, A079377, A079366-A079368.
Sequence in context: A060749 A138305 A169897 * A069933 A204987 A102347
Adjacent sequences: A079372 A079373 A079374 * A079376 A079377 A079378
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Feb 16 2003
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