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#87 by Michael De Vlieger at Sat Jan 28 10:34:58 EST 2023
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#86 by Michel Marcus at Sat Jan 28 09:20:31 EST 2023
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#85 by Michel Marcus at Sat Jan 28 09:20:21 EST 2023
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S. Seppo Mustonen, <a href="http://www.survo.fi/demos/index.html#ex51">Ulam spiral in color</a> [Interactive web page]
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#84 by Rémy Sigrist at Sat Jan 28 08:56:02 EST 2023
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#83 by Rémy Sigrist at Sat Jan 28 05:49:45 EST 2023
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<a href="/index/Con#coordinates_2D_curves">Index entries for sequences related to coordinates of 2D curves</a>
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Discussion
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| Sat Jan 28
| 08:56
| Rémy Sigrist: added index
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#82 by Sean A. Irvine at Thu Aug 19 18:08:59 EDT 2021
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#81 by William McCarty at Fri Jul 30 13:37:53 EDT 2021
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Discussion
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| Fri Jul 30
| 14:08
| Jon E. Schoenfield: Thanks for the simplification!
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| 14:17
| Jon E. Schoenfield: I don't know Maple, but since the Maple program says it's "Based on Seppo Mustonen's formula", I wonder whether its line "k:=floor(sqrt(4*(n-2)+1)) mod 4;" should be replaced by "k:=floor(sqrt(4*n-7));" or whether the program should just be left as it is.
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#80 by William McCarty at Thu Jul 29 22:06:45 EDT 2021
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a(1) = 0, a(n) = a(n-1) + sin(((floor(sqrt(4*(n4n-2)+1)) mod 4)*7))*Pi/2). For a corresponding formula for the y-coordinate, replace sin with cos. - Seppo Mustonen, Aug 21 2010 with correction by Peter Kagey, Jan 24 2016
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#79 by Jon E. Schoenfield at Thu Jul 29 21:29:45 EDT 2021
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#78 by Jon E. Schoenfield at Thu Jul 29 21:29:43 EDT 2021
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a(1) = 0, a(n) = a(n-1) + sin(mod(((floor(sqrt(4*(n-2)+1)),)) mod 4)*Pi/2). For a corresponding formula for the y-coordinate, replace sin bywith cos. - Seppo Mustonen, Aug 21 2010 with correction by Peter Kagey, Jan 24 2016
a(n) = A010751(A037458(n-1)) for n>1 - _. - _William McCarty_, Jul 29 2021
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