OFFSET
1,1
COMMENTS
The smallest number which can be expressed in 4 such ways is 554503705, which is equal to the sum of squares of the integers in the closed intervals (480,1210), (3570,3612), (3613,3654) and (7442,7451). - Giovanni Resta, Jul 25 2007
LINKS
David W. Wilson, Table of n, a(n) for n = 1..754
Sebastien DUMORTIER, Perfect Numbers [Broken link?]
EXAMPLE
147441 = 85^2 + 86^2 + ... + 101^2 = 29^2 + 30^2 + ... + 77^2 = 18^2 + 19^2 + ... + 76^2;
910805 = 550^2 + 551^2 + 552^2 = 144^2 + 145^2 + ... + 178^2 = 35^2 + 36^2 + ... + 140^2;
1026745 = 716^2 + 717^2 = 51^2 + 52^2 + ... + 147^2 = 1^2 + 2^2 + ... + 145^2;
2403800 = 583^2 + 584^2 + ... + 589^2 = 368^2 + 369^2 + ... + 384^2 = 298^2 + 299^2 + ... + 322^2;
2513434 = 473^2 + 474^2 + ... + 483^2 = 286^2 + 287^2 + ... + 313^2 = 66^2 + 67^2 + ... + 198^2;
3198550 = 225^2 + 226^2 + ... + 275^2 = 127^2 + 128^2 + ... + 226^2 = 1^2 + 2^2 + ... + 212^2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Sébastien Dumortier, Oct 06 2005
EXTENSIONS
More terms from Giovanni Resta, Jul 25 2007
STATUS
approved