login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A327273 An upper bound sequence for A327272. 2
1, 5, 105, 425, 144925, 580125, 243697125, 46420625, 253459513125 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) can be calculated by a faster algorithm than that for A327272(n). It gives a small (but not necessarily smallest) positive determinant with top row [1,2,2^2,...,2^n] and all entries integers, and rows orthogonal. Note that a(n) = A327272(n) for n=0,1 and 3. See Pinner and Smyth link below for both algorithms, and more details of the sequences.

LINKS

Table of n, a(n) for n=0..8.

Chris Pinner and Chris Smyth, Lattices of minimal index in Z^n having an orthogonal basis containing a given basis vector

Christopher J. Smyth, List of n, a(n) and associated matrix for 0 <= n <= 8

EXAMPLE

a(2) = 105 since the algorithm for a(n) produces the determinant([[1,2,4],[2,-1,0],[4,8,-5]]) = 105, having top row [1,2,2^2] and all rows orthogonal.

CROSSREFS

Sequence in context: A057016 A193340 A083252 * A034225 A273966 A114481

Adjacent sequences:  A327270 A327271 A327272 * A327274 A327275 A327276

KEYWORD

nonn,more

AUTHOR

Christopher J. Smyth, Sep 09 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 25 21:51 EST 2020. Contains 332260 sequences. (Running on oeis4.)