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A180471
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Irregular triangle in which row n has all primes q such that prime(n)*q is a base-2 Fermat pseudoprime.
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5
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31, 257, 73, 89, 683, 113, 11, 151, 331, 73, 109, 61681, 127, 337, 5419, 178481, 2796203, 157, 1613, 233, 1103, 2089, 3033169, 1321, 20857, 599479, 281, 86171, 122921, 19, 37, 109, 433, 38737, 2731, 8191, 121369, 22366891, 13367, 164511353, 8831418697, 23, 353, 397, 683, 2113, 2931542417
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OFFSET
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5,1
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COMMENTS
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The length of row n is A085014(n). The smallest and largest primes in row n are A085012(n) and A085019(n).
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REFERENCES
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LINKS
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EXAMPLE
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The irregular triangle begins
31
none
257
73
89, 683
113
11, 151, 331
73, 109
61681
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MATHEMATICA
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Flatten[Table[p=Prime[n]; q=Transpose[FactorInteger[2^(p-1)-1]][[1]]; cnt={}; Do[If[PowerMod[2, p*q[[i]]-1, p*q[[i]]]==1, AppendTo[cnt, q[[i]]]], {i, Length[q]}]; cnt, {n, 5, 50}]]
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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