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%I A186694 #39 Apr 03 2023 10:36:12
%S A186694 212159,294001,505447,584141,595631,604171,872897,971767,1062599,
%T A186694 1203623,1282529,1293671,1524181,1566691,1702357,1830661,2017963,
%U A186694 2474431,2690201,3085553,3326489,3716213,3964169,4103917,4134953,4173921,4310617,4376703
%N A186694 Numbers ending in 1, 3, 7 or 9 such that changing any one decimal digit produces a composite number.
%C A186694 Union of A050249 and A143641.
%C A186694 This sequence is infinite because Terence Tao proved that sequence A050249 is infinite.
%H A186694 Arkadiusz Wesolowski, <a href="/A186694/b186694.txt">Table of n, a(n) for n = 1..1500</a>
%H A186694 Chris Caldwell, The Prime Glossary, <a href="https://t5k.org/glossary/xpage/WeaklyPrime.html">Weakly prime</a>
%H A186694 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/9645.html">Prime Curios! 212159</a>
%H A186694 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/16579.html">Prime Curios! 17171...58369 (1000-digits)</a>
%H A186694 Terence Tao, <a href="http://arxiv.org/abs/0802.3361">A remark on primality testing and decimal expansions</a>, Journal of the Australian Mathematical Society 91:3 (2011), pp. 405-413.
%t A186694 primeProof[n_] := Module[{d, e, isPP, num}, d=IntegerDigits[n]; isPP=True; Do[e=d; e[[i]]=j; num=FromDigits[e]; If[num != n && PrimeQ[num], isPP=False; Break[]], {i, Length[d]}, {j, 0, 9}]; isPP]; Select[Range[1, 1000000, 2], Mod[#, 5] > 0 && primeProof[#] &] (* _T. D. Noe_, Feb 26 2011 *)
%Y A186694 Cf. A050249, A045572, A143641.
%K A186694 base,nonn
%O A186694 1,1
%A A186694 _Arkadiusz Wesolowski_, Feb 25 2011

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