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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A229062 1 if n is representable as sum of two nonnegative squares. 6
1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Characteristic function of A001481.

a(n) = 1 if A000161(n) > 0.

a(A022544(n)) = 0.

Multiplicative because A002654 is. - Andrew Howroyd, Aug 01 2018

LINKS

Table of n, a(n) for n=0..113.

Index entries for characteristic functions

MATHEMATICA

Join[{1}, Table[If[SquaresR[2, n]>1, 1, 0], {n, 120}]] (* Harvey P. Dale, Aug 25 2017 *)

PROG

(PARI) a(n)=my(f=0); my(r=sqrtint(n)); forstep(i=r, 1, -1, if(issquare(n-i*i), f=1; break)); f

a(n)={sumdiv( n, d, (d%4==1) - (d%4==3)) > 0} \\ Andrew Howroyd, Aug 01 2018

CROSSREFS

Cf. A002654, A070176. Partial sums are in A102548.

Sequence in context: A079559 A175480 A285568 * A014577 A157926 A263243

Adjacent sequences:  A229059 A229060 A229061 * A229063 A229064 A229065

KEYWORD

nonn,mult

AUTHOR

Ralf Stephan, Sep 17 2013

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 October 16 23:50 EDT 2019. Contains 328103 sequences. (Running on oeis4.)