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%I #18 Jun 18 2022 13:31:35
%S 4,1,1,481,3001,1111,2341,13951,5461,25261,57421,7531,123691,56581,
%T 945721,67441,1346491,325231,430711,2139271,2561161,81721,4319041,
%U 571381,4331251,1232251,7114471,3185011,407581,1500631,1846021,1346611
%N Least positive k such that 10^n + {k, k+2, k+6, k+8} are all prime.
%C For n >= 1, k == 1 (mod 30). - _Robert Israel_, May 06 2015
%H Tim Johannes Ohrtmann, <a href="/A121066/b121066.txt">Table of n, a(n) for n = 0..105</a>
%p A[0]:= 4:
%p for n from 1 to 30 do
%p for k from 1 by 30 do
%p if andmap(isprime, map(`+`,[0,2,6,8],10^n+k)) then
%p A[n]:= k; break
%p fi;
%p od od:
%p seq(A[n],n=0..30); # _Robert Israel_, May 06 2015
%t lpk[n_]:=Module[{k=1,x=10^n},While[AnyTrue[x+ k+{0,2,6,8}, CompositeQ], k++];k]; Table[lpk[n],{n,0,15}] (* The program generates the first 16 terms of the sequence. *) (* _Harvey P. Dale_, Jun 18 2022 *)
%o (PARI) print1(4,", "); n=0; until(n==100, n++; x=1; y=0; until(y==1, if(isprime(10^n+x), if(isprime(10^n+x+2), if(isprime(10^n+x+6), if(isprime(10^n+x+8), y++, x=x+30), x=x+30), x=x+30), x=x+30); if(y==1, print1(x,", ")))) \\ _Tim Johannes Ohrtmann_, May 04 2015
%o (PARI) a(n)=if(n==0, return(4)); my(k=10^n+1); while(!isprime(k) || !isprime(k+2) || !isprime(k+6) || !isprime(k+8), k+=30); k-10^n \\ _Charles R Greathouse IV_, May 06 2015
%Y Cf. A064281.
%K nonn
%O 0,1
%A _Jason Earls_, Aug 10 2006
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