A079382 -id:A079382 - cp's OEIS frontend

A079381 Costé prime expansion of Euler's constant gamma (A001620).

2, 7, 13, 19, 89, 23, 11, 131, 73, 43, 37, 7, 11, 3, 3, 3, 3, 3, 5, 2, 7, 61, 251, 41, 13, 11, 7, 23, 29, 5, 13, 11, 3, 67, 29, 7, 5, 5, 2, 17, 5, 23, 7, 11, 2, 31, 29, 5, 5, 5, 3, 3, 5, 11, 5, 7, 7, 29, 17, 5, 2, 41, 13, 13, 11, 199, 157, 101, 37, 7, 127, 29, 11, 3, 3, 5, 17, 5, 7, 5, 2, 5

Offset: 0

N. J. A. Sloane, Feb 16 2003

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).

G. C. Greubel, Table of n, a(n) for n = 0..2000
A. Costé, Sur un système fibré lié à la suite des nombres premiers, Exper. Math., 11 (2002), 383-405.

Cf. A079382, A079383, A079366-A079368.

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(gamma);

$MaxExtraPrecision = 500; P[x_] := Module[{y}, y = Ceiling[1/x]; If[PrimeQ[y], y, NextPrime[y]]]; F[x_] := Module[{y, i, t1}, y = x; t1 = {}; For[i = 1, i <= 100, i++, AppendTo[t1, p = P[y]]; y = p*y - 1]; t1]; F[EulerGamma] (* G. C. Greubel, Jan 20 2019 *)

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

A079383 Where records occur in A079381.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 23, 107, 658, 1675

Offset: 1

N. J. A. Sloane, Feb 16 2003

RECORDS transform of A079381.

N. J. A. Sloane, Transforms

Cf. A079381, A079382, A079366, A079367, A079368.

A079381 = Cases[Import["https://oeis.org/A079381/b079381.txt", "Table"], {, }][[All, 2]];
a = {}; l = 0;
For[i = 1, i <= Length[A079381], i++,
  If[A079381[[i]] > l, l = A079381[[i]]; AppendTo[a, i]]];
a (* Robert Price, Mar 15 2020 *)

a(8)-a(10) from Robert Price, Mar 15 2020

cp's OEIS Frontend

A079381 Costé prime expansion of Euler's constant gamma (A001620).

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