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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A028741 Nonsquares mod 28. 1
2, 3, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 24, 26, 27 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

Complement[Range[0, 27], PowerMod[Range[28], 2, 28]] (* Alonso del Arte, Nov 28 2019 *)

PROG

(Scala) val squaresMod28 = (1 to 28).map(n => n * n).map(_ % 28)

(0 to 27).diff(squaresMod28) // Alonso del Arte, Nov 28 2019

CROSSREFS

Cf. A010390.

Sequence in context: A317090 A179983 A065872 * A119316 A102750 A317092

Adjacent sequences:  A028738 A028739 A028740 * A028742 A028743 A028744

KEYWORD

nonn,fini,full,changed

AUTHOR

N. J. A. Sloane

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 December 7 05:14 EST 2019. Contains 329839 sequences. (Running on oeis4.)