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Search: id:A013731
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| 4, 32, 256, 2048, 16384, 131072, 1048576, 8388608, 67108864, 536870912, 4294967296, 34359738368, 274877906944, 2199023255552, 17592186044416, 140737488355328, 1125899906842624, 9007199254740992, 72057594037927936
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Starting rank of the (j-1)-Washtenaw series for the fixed ratio 2^(-j-1) (see Griess). - J. Taylor (jt_cpp(AT)yahoo.com), Apr 03 2004
1/4 + 1/32 + 1/256 + 1/2048 + ... = 2/7 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 29 2008]
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LINKS
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Tanya Khovanova, Recursive Sequences
Robert L. Griess Jr. Pieces of 2^d: Existence and uniqueness for Barnes-Wall and Ypsilanti lattices. Mar 28 2004. See Definition 14.21.
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FORMULA
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a(n)=8*a(n-1), n>0 ; a(0)=4 . G.f.: 4/(1-8x). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 23 2008]
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PROGRAM
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(Other) sage: [lucas_number1(3*n, 2, 0) for n in xrange(1, 20)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 27 2009]
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CROSSREFS
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Sequence in context: A147551 A007278 A108449 this_sequence A092811 A009509 A036725
Adjacent sequences: A013728 A013729 A013730 this_sequence A013732 A013733 A013734
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Replaced arXiv URL by non-cached version - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 23 2009
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