A162901 - OEIS

%I #14 Jun 28 2019 08:41:20

%S 1,2,3,4,5,8,14,14,15,15,22,22,26,26,27,28,34,34,38,38,39,40,46,46,50,

%T 50,51,52,58,58,62,62,63,64,65,68,74,74,75,75,82,82,86,86,87,88,94,94,

%U 98,98,99,100,106,106,115,116,117,118,118,118,122,122,123,124,125,128

%N a(1)=1. For n >= 2, a(n) = the smallest integer >= a(n-1) such that gcd(n, a(n)) = p^k, where p = prime, k >= 1.

%H Robert Israel, <a href="/A162901/b162901.txt">Table of n, a(n) for n = 1..10000</a>

%p f:= proc(n) option remember; local r;

%p       for r from procname(n-1) do

%p         if nops(ifactors(igcd(n,r))[2])=1 then return r fi

%p      od

%p end proc:

%p f(1):= 1:

%p map(f, [$1..100]); # _Robert Israel_, Jun 27 2019

%o (PARI) a=1;print1(a,",");for(n=2,100,while(omega(gcd(n,a))!=1,a++);print1(a,",")) \\ _Hagen von Eitzen_, Oct 03 2009

%Y Cf. A162900.

%K nonn

%O 1,2

%A _Leroy Quet_, Jul 16 2009

%E More terms from _Hagen von Eitzen_, Oct 03 2009