login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A086719 Numbers n == 1, 2, 5 or 6 (mod 8) such that there is only one solution to i^2+j^2+k^2=n, i >= j >= k >= 0. 1
1, 2, 5, 6, 10, 13, 14, 21, 22, 30, 37, 42, 46, 58, 70, 78, 93, 133, 142, 190, 253 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..21.

P. T. Bateman and E. Grosswald, Positive integers expressible as a sum of three squares in essentially only one way, J. Number Theory, 19 (1984), 301-308.

MATHEMATICA

aQ[n_] := MemberQ[{1, 2, 5, 6}, Mod[n, 8]] && Length[Solve[i^2+j^2+k^2==n && k>=0 && j>=k && i>=j, {i, j, k}, Integers]]==1; Select[Range[260], aQ] (* Amiram Eldar, Dec 04 2018 *)

CROSSREFS

Cf. A085616.

Sequence in context: A047440 A255055 A007674 * A115200 A075823 A191748

Adjacent sequences:  A086716 A086717 A086718 * A086720 A086721 A086722

KEYWORD

nonn,fini,full

AUTHOR

N. J. A. Sloane, Jul 31 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 22 05:03 EDT 2019. Contains 323473 sequences. (Running on oeis4.)