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A090325 Least (distinct) k such that k, k+n, k+2n are all composite. Rearrangement of composite numbers. 1

%I #10 Nov 20 2017 05:34:28

%S 8,4,6,10,15,9,14,12,16,18,22,20,25,21,24,26,28,27,30,32,33,34,35,36,

%T 38,39,42,40,46,44,49,48,45,50,51,52,54,56,55,58,63,57,62,60,65,64,68,

%U 66,70,69,72,74,76,75,77,78,81,80,82,84,85,86,87,88,90,92,91,94,93,95,98

%N Least (distinct) k such that k, k+n, k+2n are all composite. Rearrangement of composite numbers.

%H Robert Israel, <a href="/A090325/b090325.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 100: # to get all terms before the first term > N

%p Avail:= remove(isprime, [$4..N]):

%p for n from 1 while Avail <> [] do

%p for a in Avail while isprime(a+n) or isprime(a+2*n) do od:

%p if a = Avail[-1] and isprime(a+n) or isprime(a+2*n) then break fi;

%p A[n]:= a;

%p Avail:= subs(a=NULL, Avail);

%p od:

%p seq(A[i],i=1..n-1); # _Robert Israel_, Nov 19 2017

%K nonn

%O 1,1

%A _Amarnath Murthy_, Dec 02 2003

%E More terms from _David Wasserman_, Nov 04 2005

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)