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Search: id:A132066
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| A132066 |
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Irregular array: the sum of the first m terms of row n is the m-th positive divisor of n. |
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+0
1
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| 1, 1, 1, 1, 2, 1, 1, 2, 1, 4, 1, 1, 1, 3, 1, 6, 1, 1, 2, 4, 1, 2, 6, 1, 1, 3, 5, 1, 10, 1, 1, 1, 1, 2, 6, 1, 12, 1, 1, 5, 7, 1, 2, 2, 10, 1, 1, 2, 4, 8, 1, 16, 1, 1, 1, 3, 3, 9, 1, 18, 1, 1, 2, 1, 5, 10, 1, 2, 4, 14, 1, 1, 9, 11, 1, 22, 1, 1, 1, 1, 2, 2, 4, 12, 1, 4, 20, 1, 1, 11, 13, 1, 2, 6, 18, 1, 1, 2, 3
(list; graph; listen)
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OFFSET
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1,5
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COMMENT
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Row n contains A000005(n) terms.
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EXAMPLE
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The positive divisors of 20 are 1,2,4,5,10,20. Row 20 of the array is 1,1,2,1,5,10. So we have 1=1; 1+1=2; 1+1+2=4; 1+1+2+1=5; 1+1+2+1+5=10; 1+1+2+1+5+10=20.
The first 10 rows:
1;
1,1;
1,2;
1,1,2;
1,4;
1,1,1,3
1,6;
1,1,2,4;
1,2,6;
1,1,3,5
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MATHEMATICA
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f[n_] := Block[{d}, d = Divisors[n]; d - Prepend[Most[d], 0]]; Flatten[Array[f, 40]] (*Chandler*)
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CROSSREFS
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Cf. A027750, A000005.
Sequence in context: A071628 A033809 A046067 this_sequence A102190 A138650 A137843
Adjacent sequences: A132063 A132064 A132065 this_sequence A132067 A132068 A132069
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KEYWORD
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nonn,tabf
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Oct 30 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 01 2007
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