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Costé prime expansion of Pi-e.
2

%I #11 Oct 27 2015 05:03:01

%S 3,5,3,23,11,3,7,5,3,37,13,11,2,17,11,3,17,11,2,29,5,29,11,3,3,5,5,

%T 479,89,23,17,11,3,5,3,7,5,5,7,5,2,11,5,3,7,5,2,5,5,29,5,5,7,11,5,7,7,

%U 7,17,5,7,5,13,23,11,3,29,23,7,3,11,3,5,19,53,19,23,29,67,1409,347,37,13,13

%N Costé prime expansion of Pi-e.

%C For x in (0,1], define P(x) = min{p: p prime, 1/x < p}, Phi(x) = P(x)x - 1. Costé 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).

%H A. Costé, <a href="http://www.emis.de/journals/EM/expmath/volumes/11/11.3/Coste383_405.pdf">Sur un système fibré lié à la suite des nombres premiers</a>, Exper. Math., 11 (2002), 383-405.

%p Digits := 500: 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 100 do p := P(y); t1 := [op(t1),p]; y := p*y-1; od; t1; end; F(Pi-exp(1));

%Y Cf. A079385, A079386, A079366, A079367, A079368, A080348.

%K nonn,easy

%O 0,1

%A Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 17 2003