OFFSET
1,15
COMMENTS
a(n) ignores the order of the five squares. If we count all 5-plets whose squares sum to a square, including repetitions, then the limit as n goes to infinity of the ratio of this number to a(n) is 5/4.
FORMULA
a(n) = A025444(n^2). [From R. J. Mathar, Oct 18 2010]
EXAMPLE
For n=17 a(17)=3 since 17^2 can be expressed as the sum of 5 different squares in 3 ways: 17^2 = 14^2+8^2+4^2+3^2+2^2 = 13^2+8^2+6^2+4^2+2^2 = 12^2+10^2+5^2+4^2+2^2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Carmine Suriano, Jun 21 2010
STATUS
approved