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Search: id:A120579
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| A120579 |
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Irregular array where the n-th row are the divisors, not occurring earlier in the sequence, of the sum of the terms in all previous rows. a(1)=5. |
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+0
4
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| 5, 1, 2, 3, 6, 17, 34, 4, 68, 7, 10, 14, 20, 28, 35, 70, 140, 8, 16, 29, 58, 116, 232, 464, 19, 73, 1387, 1433, 2866, 7165, 14330, 5732, 28660, 11, 22, 44, 15763, 31526, 63052, 38, 55, 83, 95, 110, 166, 190, 209, 415, 418, 830, 913, 1045, 1577, 1826, 2090, 3154, 4565
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Is this sequence a permutation of the positive integers?
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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Array begins:
5
1
2,3,6
17
34
Now these terms add up to 68. So row 6 is the divisors of 68 which do not occur earlier in the sequence. 1, 2, 17 and 34 occur in earlier rows, so row 6 is (4,68).
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MATHEMATICA
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f[t_] := Flatten[Append[t, Select[Divisors[Plus @@ t], FreeQ[t, # ] &]]]; Nest[f, {5}, 14] (*Chandler*)
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CROSSREFS
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Cf. A120576, A120577, A120578.
Sequence in context: A046771 A029762 A055185 this_sequence A093316 A085758 A154529
Adjacent sequences: A120576 A120577 A120578 this_sequence A120580 A120581 A120582
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KEYWORD
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nonn,tabf
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AUTHOR
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Leroy Quet Jun 15 2006
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jun 17 2006
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