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%I #11 May 09 2020 13:49:56
%S 1,49,91,1117,2929,721,1819,37237,30979,30967,29629,6457,53269,27727,
%T 271159,556651,190489,62797,105259,784777,290659,1320829,438037,
%U 1019317,333991,248371,226609,671227,384571,1573537,366841,954391,1701247,540811,1105291
%N Smallest k such that (10^n+k, 10^n+k+2) and (10^(n+1)+k, 10^(n+1)+k+2) are two pairs of twin primes.
%H Pierre CAMI, <a href="/A224905/b224905.txt">Table of n, a(n) for n = 1..76</a>
%e 10^1+1=11 prime as 13 10^2+1=101 prime as 103 so a(1)=1.
%t sk[n_]:=Module[{k=1},While[!AllTrue[{10^n+k,10^n+k+2,10^(n+1)+k,10^(n+1)+k+2},PrimeQ],k++];k]; Array[sk,35] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, May 09 2020 *)
%o PFGW & SCRIPTIFY
%o SCRIPT
%o DIM n, 0
%o DIM k, -1
%o DIMS t
%o OPENFILEOUT myf, a(n).txt
%o LABEL a
%o SET n, n+1
%o SET k,-1
%o LABEL b
%o SET k, k+2
%o SETS t, %d, %d\,; n; k
%o PRP 10^n+k, t
%o IF ISPRP THEN GOTO c
%o GOTO b
%o LABEL c
%o PRP 10^n+k+2, t
%o IF ISPRP THEN GOTO d
%o GOTO b
%o LABEL d
%o PRP 10^(n+1)+k, t
%o IF ISPRP THEN GOTO e
%o GOTO b
%o LABEL e
%o PRP 10^(n+1)+k+2, t
%o IF ISPRP THEN GOTO f
%o GOTO b
%o LABEL f
%o WRITE myf, t
%o SET k, k+2
%o GOTO a
%Y Cf. A124001, A224846.
%K nonn
%O 1,2
%A _Pierre CAMI_, Jul 25 2013
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