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A065545
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a(n) is smallest prime > 2*a(n-1), a(1) = 3.
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4
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3, 7, 17, 37, 79, 163, 331, 673, 1361, 2729, 5471, 10949, 21911, 43853, 87719, 175447, 350899, 701819, 1403641, 2807303, 5614657, 11229331, 22458671, 44917381, 89834777, 179669557, 359339171, 718678369, 1437356741, 2874713497
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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NextPrim[n_Integer] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; Return[k]]; a[1] = 3; a[n_] := NextPrim[ 2*a[n - 1]]; Table[ a[n], {n, 1, 20} ]
NestList[NextPrime[2*#] &, 3, 29] (* Zak Seidov, Feb 04 2016 *)
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PROG
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(PARI) lista(nn) = {print1(a = 3, ", "); for (n=1, nn, a = nextprime(2*a+1); print1(a, ", "); ); } \\ Michel Marcus, Feb 04 2016
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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