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A051333
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Euclid-Mullin sequence (A000945) with initial value a(1)=257 instead of a(1)=2.
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1
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257, 2, 5, 3, 11, 84811, 31, 7, 1560842137471, 20113, 17, 83, 47, 339491, 7814561, 109, 2897, 16103, 70921439, 199, 1381, 34987489236924545883729121, 43, 241, 37, 491, 28468486915378661, 8803, 29, 25212511, 2311, 67, 3929, 1151, 192697, 797, 157, 23, 1489, 13
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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a[1]=257; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
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PROG
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(PARI) spf(n)=my(f=factor(n)[1, 1]); f \\ A020639
first(m)=my(v=vector(m)); v[1]=257; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 07 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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