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A186694
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Numbers ending in 1, 3, 7 or 9 such that changing any one decimal digit produces a composite number.
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1
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212159, 294001, 505447, 584141, 595631, 604171, 872897, 971767, 1062599, 1203623, 1282529, 1293671, 1524181, 1566691, 1702357, 1830661, 2017963, 2474431, 2690201, 3085553, 3326489, 3716213, 3964169, 4103917, 4134953, 4173921, 4310617, 4376703
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OFFSET
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1,1
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COMMENTS
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This sequence is infinite because Terence Tao proved that sequence A050249 is infinite.
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LINKS
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MATHEMATICA
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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 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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