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Search: id:A075616
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| A075616 |
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Rearrangement of natural numbers so that starting with a(n) the concatenation of n numbers gives a prime. |
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+0
3
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| 2, 1, 3, 4, 7, 5, 9, 6, 17, 8, 43, 10, 19, 11, 13, 12, 33, 14, 37, 15, 23, 16, 113, 18, 73, 20, 51, 21, 103, 22, 61, 24, 87, 25, 49, 26, 67, 27, 117, 28, 57, 29, 71, 30, 79, 31, 283, 32, 239, 34, 81, 35, 143, 36, 151, 38, 139, 39, 147, 40, 289, 41, 161, 42, 351, 44, 129, 45
(list; graph; listen)
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OFFSET
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1,1
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MATHEMATICA
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a = {2, 1, 3}; f[n_] := Block[{k = 1, b = Take[a, {n, 2n - 3}]}, While[Position[a, k] != {}, k++ ]; b = Join[b, IntegerDigits[k]]; a = Append[a, k]; While[ Position[a, k] != {} || !PrimeQ[ FromDigits[ Join[ b, IntegerDigits[k]]]], k++ ]; a = Append[a, k]]; Do[ f[n], {n, 3, 40}]; a
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CROSSREFS
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Cf. A075617 and A073672.
Sequence in context: A139374 A111958 A160187 this_sequence A160186 A050041 A058658
Adjacent sequences: A075613 A075614 A075615 this_sequence A075617 A075618 A075619
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 29 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 02 2002
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