A295486 Numbers that have exactly three representations as a sum of six nonnegative squares.

9, 12, 13, 14, 16, 19, 23

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 one more square, 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

Table of n, a(n) for n=1..7.

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

Cf. A000177, A294524, A295150.

Sequence in context: A110647 A347943 A335168 * A032687 A351042 A259313

Adjacent sequences: A295483 A295484 A295485 * A295487 A295488 A295489

Keyword

nonn,fini,full

Author

Robert Price, Nov 22 2017

Status

approved