The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A055672

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A055672

Number of right-inequivalent prime Hurwitz quaternions of norm n.
(history; published version)

#13 by Alois P. Heinz at Sun Oct 23 12:53:08 EDT 2016

STATUS

reviewed

approved

#12 by Joerg Arndt at Sun Oct 23 11:09:11 EDT 2016

STATUS

proposed

reviewed

#11 by Jean-François Alcover at Sat Oct 22 13:09:32 EDT 2016

STATUS

editing

proposed

Discussion

Sat Oct 22

13:27

Joerg Arndt: Let's keep this unapproved to address the suggestions in the "extensions" section, OK?

Sun Oct 23

02:35

Jean-François Alcover: I don't mind (though I don't clearly understand).

11:09

Joerg Arndt: OK the, let's finish this edit.

#10 by Jean-François Alcover at Sat Oct 22 13:09:24 EDT 2016

MATHEMATICA

A055671[n_] := If[PrimeQ[n], Reduce[a^2 + b^2 + c^2 + d^2 == 4n, {a, b, c, d}, Integers] // Length, 0]; a[n_] := A055671[n]/24; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Oct 22 2016 *)

STATUS

approved

editing

#9 by Charles R Greathouse IV at Sun Aug 28 18:18:34 EDT 2016

LINKS

R. J. Mathar, <a href="/A055672/b055672.txt">Table of n, a(n) for n = 0..10000</a>

Discussion

Sun Aug 28

18:18

OEIS Server: https://oeis.org/edit/global/2560

#8 by Jon E. Schoenfield at Sat Jul 11 00:21:14 EDT 2015

STATUS

editing

approved

#7 by Jon E. Schoenfield at Sat Jul 11 00:21:12 EDT 2015

EXTENSIONS

I would also like to get the sequences of inequivalent prime Hurwitz quaternions, where two primes are considered equivalent if they differ by left or right multiplication by one of the 24 units. This will give two more sequences, analogues analogs of A055670 and A055672.

STATUS

approved

editing

#6 by Russ Cox at Fri Mar 30 16:48:50 EDT 2012

AUTHOR

_N. J. A. Sloane (njas(AT)research.att.com), _, Jun 09 2000

Discussion

Fri Mar 30

16:48

OEIS Server: https://oeis.org/edit/global/110

#5 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

R. J. Mathar, <a href="/A055672/b055672.txt">Table of n, a(n) for n=0..10000</a>

KEYWORD

nonn,easy,nice,new

#4 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

LINKS

R. J. Mathar, <a href="http://www.research.att.com/~njas/sequences/b055672.txt">Table of n, a(n) for n=0..10000</a>

KEYWORD

nonn,easy,nice,new

AUTHOR

N. J. A. Sloane (njas, (AT)research.att.com), Jun 09 2000