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Search: id:A129773
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| A129773 |
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Each row is a finite sequence of N terms a0,a1,...,ai,...,an which satisfies the conditions written in the following array: "In this array, there are a0 times the number 0 there are a1 times the number 1 ..... ..... there are ai times the number i ..... ..... the are an times the number n. |
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1
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| 1, 2, 3, 2, 1, 4, 3, 2, 2, 1, 1, 1, 5, 3, 2, 1, 2, 1, 1, 1, 6, 3, 2, 1, 1, 2, 1, 1, 1, 7, 3, 2, 1, 1, 1, 2, 1, 1
(list; graph; listen)
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OFFSET
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3,2
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COMMENT
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In the generating array as above, the total of the first column of numbers is 2+2*n, the total of the second column is n*(n+1)/2, the total of all the numbers is (n+1)*(n+4)/2 and is equal to the sum of all the products i*ai. These properties are useful to get a fast computation.
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FORMULA
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For n<6, exists only a sequence of 4 terms (n=3) ( 1,2,3,2) For n>=6 exist always a sequence with a0=1 a1=n-2 a2=3 a3=2 a(n-2)=2 all others ai=1
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EXAMPLE
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In this array there is once the number 0
there are 2 times the number 1
there are 3 times the number 2
there are 2 times the number 3
so the first row is 1,2,3,2
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CROSSREFS
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Sequence in context: A106559 A106377 A118457 this_sequence A105789 A076549 A104411
Adjacent sequences: A129770 A129771 A129772 this_sequence A129774 A129775 A129776
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KEYWORD
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fini,nonn,uned
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AUTHOR
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Philippe LALLOUET (philip.lallouet(AT)wanadoo.fr), Jun 08 2007
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