A047701 All positive numbers that are not the sum of 5 nonzero squares.

1, 2, 3, 4, 6, 7, 9, 10, 12, 15, 18, 33

Offset

1,2

References

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 33, pp 12, Ellipses, Paris 2008.

E. Grosswald, Representations of Integers as Sums of Squares. Springer-Verlag, NY, 1985, Theorem 2., p. 73.

Ivan Niven and Herbert S. Zuckerman, An Introduction to the Theory of Numbers, New York: John Wiley (1980), p. 145

Links

Table of n, a(n) for n=1..12.

Index entries for sequences related to sums of squares

Example

4 = 1^2 + 1^2 + 1^2 + 1^2 + 0^2, but the last square is 0, and hence 4 is in the sequence.
5 = 1^2 + 1^2 + 1^2 + 1^2 + 1^2, and therefore 5 is not in the sequence.

Mathematica

Select[ Range[100], Select[ PowersRepresentations[#, 5, 2], FreeQ[#, 0]& ] == {}& ] (* Jean-François Alcover, Sep 03 2013 *)

Crossrefs

Cf. A047700, A000534, A180968 (not the sum of 6 squares).

Sequence in context: A246372 A006254 A111333 * A164528 A127963 A031403

Adjacent sequences: A047698 A047699 A047700 * A047702 A047703 A047704

Keyword

nonn,full,fini

Author

Arlin Anderson (starship1(AT)gmail.com)

Extensions

Name changed. - Wolfdieter Lang, Mar 28 2013

Status

approved