%I #10 Oct 30 2017 22:39:47

%S 1,3,4,7,8,13,14,19,20,27,31,32,39,43,44,49,54,61,62,69,73,74,81,85,

%T 91,99,103,104,109,110,117,128,133,138,143,150,157,158,165,169,174,

%U 181,182,193,194,199,200,213,224,229,230,237,241,242,255,259,264,271,272,279

%N a(0)=1. a(n) = the smallest integer coprime to a(n-1) and greater than the n-th prime.

%H Michael De Vlieger, <a href="/A157419/b157419.txt">Table of n, a(n) for n = 0..10000</a>

%e a(8) = 20, and the 9th prime is 23. So for a(9) we want the smallest integer that is both coprime to 20 and is > 23. Checking: 24 is not coprime to 20. 25 is not coprime to 20. 26 is not coprime to 20. But 27 is coprime to 20, so a(9) = 27.

%t Fold[Append[#1, Block[{k = Prime@ #2 + 1}, While[! CoprimeQ[k, #1[[-1]] ], k++]; k]] &, {1}, Range@ 59] (* _Michael De Vlieger_, Oct 30 2017 *)

%Y Cf. A157420, A157421.

%K nonn

%O 0,2

%A _Leroy Quet_, Feb 28 2009

%E Extended by _Ray Chandler_, Jun 19 2009