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A080348 Costé prime expansion of Catalan's constant. 3
2, 2, 2, 5, 2, 5, 3, 7, 11, 5, 11, 7, 23, 13, 11, 3, 5, 2, 7, 5, 3, 7, 5, 13, 43, 43, 29, 17, 5, 2, 19, 11, 5, 3, 7, 5, 5, 3, 7, 7, 11, 3, 3, 7, 11, 2, 13, 7, 19, 13, 11, 11, 5, 3, 3, 3, 7, 7, 11, 3, 3, 7, 13, 37, 17, 7, 3, 7, 5, 5, 5, 2, 11, 5, 5, 5, 5, 2, 5, 5, 37, 7, 157, 53, 1361, 131, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

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).

LINKS

Table of n, a(n) for n=0..86.

A. Costé, Sur un système fibré lié à la suite des nombres premiers, Exper. Math., 11 (2002), 383-405.

MAPLE

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(Catalan);

CROSSREFS

Cf. A079385, A079386, A079366, A079367, A079368.

Sequence in context: A260587 A095370 A046053 * A096396 A029662 A077913

Adjacent sequences:  A080345 A080346 A080347 * A080349 A080350 A080351

KEYWORD

nonn,easy

AUTHOR

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

STATUS

approved

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Last modified August 2 11:06 EDT 2021. Contains 346422 sequences. (Running on oeis4.)