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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156476 Number of n X n 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.

License Agreements, Terms of Use, Privacy Policy .

Last modified August 27 00:05 EDT 2016. Contains 275900 sequences.