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Search: id:A011922
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| A011922 |
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(2+sqrt(1+((((2+sqrt(3))^(2*n)-(2-sqrt(3))^(2*n))^2)/4)))/3. |
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+0
6
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| 1, 3, 33, 451, 6273, 87363, 1216801, 16947843, 236052993, 3287794051, 45793063713, 637815097923, 8883618307201, 123732841202883, 1723376158533153, 24003533378261251, 334326091137124353
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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Mario Velucchi, Seeing couples, in Recreational and Educational Computing, to appear 1997.
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FORMULA
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sqrt 3 = 1 + Sum(1 through infinity) 2/a(n) = 2/2 + 2/3 + 2/33 + 2/451 + 2/6273 + 2/87363 + 2/1216801... - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jun 12 2003
a(n)^2 = A103974(n+1)^2 - (4*A007655(n+1))^2. - Paul D. Hanna (pauldhanna(AT)juno.com), Mar 06 2005
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CROSSREFS
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Cf. A011916, A011918, A011920.
Cf. A103974, A007655.
Adjacent sequences: A011919 A011920 A011921 this_sequence A011923 A011924 A011925
Sequence in context: A163476 A155660 A009502 this_sequence A071405 A092170 A083080
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KEYWORD
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nonn,easy
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AUTHOR
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Mario Velucchi (mathchess(AT)velucchi.it)
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EXTENSIONS
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Formula corrected by Francisco Salinas (franciscodesalinas(AT)hotmail.com), Dec 30 2001
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