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Search: id:A067771
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| A067771 |
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Number of vertices in Sierpinski triangle of order n. |
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+0
1
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| 3, 6, 15, 42, 123, 366, 1095, 3282, 9843, 29526, 88575, 265722, 797163, 2391486, 7174455, 21523362, 64570083, 193710246, 581130735, 1743392202, 5230176603, 15690529806, 47071589415, 141214768242, 423644304723, 1270932914166
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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This sequence represents another link from the product factor space Q X Q / {(1,1), (-1, -1)} to Sierpinski's triangle. The first "link" found was to sequence A048473. - Creighton Dement (creighton.k.dement(AT)uni-oldenburg.de), Aug 05 2004
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REFERENCES
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Peter Wessendorf and Kristina Downing, personal communication.
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LINKS
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C. Lanius, Fractals
Eric Weisstein's World of Mathematics, Sierpinski Graph
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FORMULA
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a(n) = 3 + 3^1 + 3^2 + 3^3 + 3^4 +...+ 3^n
a(1)=3, a(n)=a(n-1)+3^n. a(n)=(3/2)(1+3^n). - Zak Seidov, Mar 19 2007
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CROSSREFS
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This is 3*A007051. Cf. A048473.
Sequence in context: A098701 A001433 A005368 this_sequence A056382 A028401 A005655
Adjacent sequences: A067768 A067769 A067770 this_sequence A067772 A067773 A067774
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KEYWORD
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nonn,easy
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AUTHOR
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Martin Wessendorf (martinw(AT)mail.ahc.umn.edu), Feb 09 2002
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EXTENSIONS
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More terms from Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 22 2002
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