login
This site is supported by donations to The OEIS Foundation.

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156476 Number of nXn arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 21. 0
54, 20, 3552, 11364, 2742240, 56271108, 23882769984, 990946452040, 760348893638560 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

LINKS

Table of n, a(n) for n=4..12.

CROSSREFS

Sequence in context: A096510 A236178 A247389 * A137939 A033374 A247897

Adjacent sequences:  A156473 A156474 A156475 * A156477 A156478 A156479

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 09 2009

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified August 29 04:48 EDT 2015. Contains 261184 sequences.