The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A053761 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A053761

Least positive integer k for which the Jacobi symbol (k|2*n-1) is less than 1, where 2*n-1 is a nonsquare; a(n)=0 if 2*n-1 is a square.
(history; published version)

#32 by Georg Fischer at Fri Apr 19 02:52:42 EDT 2019

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editing

approved

#31 by Georg Fischer at Fri Apr 19 02:52:36 EDT 2019

REFERENCES

S. Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 443-448.

P. Paulo Ribenboim, The New Book of Prime Number Records, 3rd ed., Springer-Verlag 1996; Math. Rev. 96k:11112.

LINKS

S. Steven R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/constant/hdmrd/jacobi.html">Quadratic Residues</a> [Broken link]

Steven R. Finch, <a href="http://web.archive.org/web/20010208112444/http://www.mathsoft.com/asolve/constant/hdmrd/jacobi.html">Quadratic Residues</a> [From the Wayback machine]

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approved

editing

#30 by Bruno Berselli at Wed Jul 04 08:46:56 EDT 2018

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reviewed

approved

#29 by Michel Marcus at Wed Jul 04 07:21:49 EDT 2018

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proposed

reviewed

#28 by Jon E. Schoenfield at Wed Jul 04 05:30:25 EDT 2018

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editing

proposed

#27 by Jon E. Schoenfield at Wed Jul 04 05:30:23 EDT 2018

PROG

for(n=1, 10000, write("b053761.txt", n, " ", A053761(n))); \\ From __Antti Karttunen_, May 10 2017

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approved

editing

#26 by Jon E. Schoenfield at Sat Oct 07 01:12:26 EDT 2017

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proposed

approved

#25 by Jon E. Schoenfield at Sat Oct 07 01:12:20 EDT 2017

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editing

proposed

#24 by Jon E. Schoenfield at Sat Oct 07 01:12:13 EDT 2017

MATHEMATICA

a[n_] := If[IntegerQ[Sqrt[2*n - 1]], Return[0], For[ k = 1, True, k++, If[ JacobiSymbol[k, 2*n - 1] < 1 , Return[k]]]]; Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Jun 20 2013, after _R. J. Mathar _ *)

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approved

editing

#23 by N. J. A. Sloane at Wed May 10 17:45:39 EDT 2017

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proposed

approved