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A107350
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Number of isogons with a certain property.
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3
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1, 4, 34, 346, 3965, 48396, 615966, 8082457, 108545916, 1484716135, 20612084010, 289688970195, 4113620233260, 58930127470164, 850641610106596, 12360278974175769, 180648953113093368, 2653875476976308643, 39167191622334514398, 580439539153823110678, 8633956582855204662785
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| This and A060005 appear in the reference as incidental sequences when computing A007219.
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REFERENCES
| L. Sallows, M. Gardner, R. K. Guy and D. E. Knuth, Serial isogons of 90 degrees, Math. Mag. 64 (1991), 315-324.
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FORMULA
| product[ {1+x^(2i+1)},i=0,1,...,4n-1] = 1+...+2*a(n)*x^(8n^2)+.... (g.f.) - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 08 2007
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MAPLE
| A107350 := proc(n) res := 1 ; for i from 0 to 4*n-1 do res := taylor(res*(1+x^(2*i+1)), x=0, 8*n^2+1) ; od ; coeftayl(res, x=0, 8*n^2)/2 ; end: for n from 1 to 25 do printf("%d, ", A107350(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 08 2007
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CROSSREFS
| Cf. A007219, A060005.
Sequence in context: A005569 A025572 A093137 * A206180 A199752 A084973
Adjacent sequences: A107347 A107348 A107349 * A107351 A107352 A107353
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 23 2005
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 08 2007
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