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Search: id:A133283
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| A133283 |
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Numbers n such that 30*n^2+6 is a square. |
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+0
1
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| 1, 23, 505, 11087, 243409, 5343911, 117322633, 2575754015, 56549265697, 1241508091319, 27256628743321, 598404324261743, 13137638505015025, 288429642786068807, 6332314502788498729, 139022489418560903231
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OFFSET
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1,2
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FORMULA
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a(n+2) = 22*a(n+1)-a(n) ; a(n+1)=11*a(n)+2*(30*a(n)^2+6)^0.5
a(n)=(sqrt(30)/10 - 1/2)(11 + 2sqrt(30))^n - (sqrt(30)/10 + 1/2)(11 - 2sqrt(30))^n. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 24 2007
G.f.: x*(1+x)/(1-22*x+x^2). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 14 2007
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MAPLE
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a[1]:=1: a[2]:=23: for n to 14 do a[n+2]:=22*a[n+1]-a[n] end do: seq(a[n], n= 1..16); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 24 2007
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CROSSREFS
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Sequence in context: A095256 A015678 A014905 this_sequence A121903 A136285 A114926
Adjacent sequences: A133280 A133281 A133282 this_sequence A133284 A133285 A133286
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KEYWORD
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nonn
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AUTHOR
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Richard Choulet (richardchoulet(AT)yahoo.fr), Oct 16 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 24 2007
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