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Search: id:A121390
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| A121390 |
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Sequence generated by the recurrence below begins with exactly seven primes. |
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2
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| 2, 8607769, 25823309, 222281113118699, 5740034091209256896999, 1275901167133279185594625154673899999, 7323716196358702385046852882006552347670105360888299999999
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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This sequence has the smallest value of a(1) for a(0) = 2 and this recurrence such that the first seven terms are primes. The first composite term is too large to include. Note also that each a(n) has Fibonacci(n) trailing 9s (see A121389).
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FORMULA
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a(0) = 2; a(1) = 8607769; a(n) = a(n-2)*a(n-1) + a(n-2) + a(n-1).
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EXAMPLE
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a(2) = 25823309 = 2*8607769 + 2 + 8607769 and is prime.
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CROSSREFS
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Cf. A000045, A063896, A121389.
Sequence in context: A158347 A133495 A157991 this_sequence A157992 A135235 A053823
Adjacent sequences: A121387 A121388 A121389 this_sequence A121391 A121392 A121393
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KEYWORD
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nonn
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AUTHOR
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Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 26 2006
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