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A295747
Numbers that have exactly six representations of a sum of seven nonnegative squares.
0
21, 22, 26, 27, 32
OFFSET
1,1
COMMENTS
This sequence is finite and complete. See the von Eitzen Link and the proof in A294675 stating that for n > 5408, the number of ways to write n as a sum of 5 squares (without allowing zero squares) is at least floor(sqrt(n - 101) / 8) = 9. Since this sequence relaxes the restriction of zero squares and allows two more zero squares, the number of representations for n > 5408 is at least nine. Then an inspection of n <= 5408 completes the proof.
REFERENCES
E. Grosswald, Representations of Integers as Sums of Squares. Springer-Verlag, New York, 1985, p. 86, Theorem 1.
LINKS
H. von Eitzen, in reply to user James47, What is the largest integer with only one representation as a sum of five nonzero squares? on stackexchange.com, May 2014
D. H. Lehmer, On the Partition of Numbers into Squares, The American Mathematical Monthly, Vol. 55, No. 8, October 1948, pp. 476-481.
CROSSREFS
Sequence in context: A323419 A333908 A241851 * A125737 A349248 A160782
KEYWORD
nonn,fini,full
AUTHOR
Robert Price, Nov 26 2017
STATUS
approved