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A247561
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Indices of primes in the tetranacci sequence A000288.
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6
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5, 6, 10, 11, 12, 13, 18, 30, 31, 36, 38, 97, 108, 150, 196, 221, 277, 532, 596, 2468, 2691, 3773, 4303, 5755, 8925, 10083, 11708, 14080, 19990, 24102, 34767, 35973, 39238, 49760, 97706
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OFFSET
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1,1
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COMMENTS
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a(36) > 2*10^5.
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LINKS
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MATHEMATICA
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a={1, 1, 1, 1}; For[n=4, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[4]]=sum]
Flatten[Position[LinearRecurrence[{1, 1, 1, 1}, {1, 1, 1, 1}, 10^5], _?PrimeQ]]- 1 (* Harvey P. Dale, Dec 20 2016 *)
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CROSSREFS
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Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288.
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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