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Search: id:A142884
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| A142884 |
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Prime finding sequence recursion where the primes are sums of two integers: a(n)=If( a(n-1)=prime,1, else a(n-2)+a(n-3)). |
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+0
1
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| 0, 1, 1, 1, 2, 1, 3, 1, 4, 4, 5, 1, 9, 6, 10, 15, 16, 25, 31, 1, 56, 32, 57, 88, 89, 1, 177, 90, 178, 267, 268, 445, 535, 713, 980, 1248, 1693, 1, 2941, 1694, 2942, 4635, 4636, 7577, 1, 12213, 7578, 12214, 19791, 19792, 32005, 39583, 51797, 1, 91380, 51798, 91381, 1
(list; graph; listen)
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OFFSET
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1,5
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FORMULA
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a(n)=If( a(n-1)=prime,1, else a(n-2)+a(n-3)).
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EXAMPLE
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15+ 16= 31,
32+ 57= 89,
713+ 980= 1693,
19792+ 32005= 51797,
237122034+ 314186695=551308729.
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MATHEMATICA
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Clear[a, n]; a[0] = 0; a[1] = 1; a[2] = 1; a[n_] := a[n] = If[PrimeQ[a[n - 1]], 1, a[n - 2] + a[n - 3]]; Table[a[n], {n, 0, 100}]
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CROSSREFS
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Sequence in context: A036445 A098910 A165025 this_sequence A142878 A082904 A034868
Adjacent sequences: A142881 A142882 A142883 this_sequence A142885 A142886 A142887
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KEYWORD
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nonn,uned
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 28 2008
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