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Search: id:A087085
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| A087085 |
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Sum of the integer elements in the subsets of the subsets of the integers 1 to n. |
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+0
1
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| 0, 0, 2, 48, 3072, 2621440, 515396075520, 6198106008766409342976, 304893000761160863263183648258864317464576
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OFFSET
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0,3
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REFERENCES
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Alan Sutcliffe, Divisors and Common Factors in Sets of Integers, awaiting publication.
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FORMULA
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n*(n-1)*2^(n-4+2^(n-1))
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EXAMPLE
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a(3)=48 since the 16 subsets of the sets ( ) (1) (2) (1,2) are ( ) (( )) ((1)) ((2)) ((1,2)) (( ) (1)) (( ) (2)) (( ) (1,2)) ((1) (2)) ((1) (1,2)) ((2) (1,2)) (( ) (1) (2)) (( ) (1) (1,2)) (( ) (2) (1,2)) ((1) (2) (1,2)) (( ) (1) (2) (1,2)) and the sum of the 32 integer elements is 48.
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CROSSREFS
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A001146 gives the number of subsets of the subsets of the integers 1 to n. A028369 gives the number of subset elements in the subsets of the subsets of the integers 1 to n. A087084 gives the number of integer elements in the subsets of the subsets of the integers 1 to n.
Adjacent sequences: A087082 A087083 A087084 this_sequence A087086 A087087 A087088
Sequence in context: A119698 A112103 A114714 this_sequence A067626 A053071 A002820
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KEYWORD
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easy,nonn
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AUTHOR
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Alan Sutcliffe (alansut(AT)ntlworld.com), Aug 13 2003
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