login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A227453 Numbers k such that the distance to the largest square less than k is a multiple of 4. 2
8, 13, 20, 24, 29, 33, 40, 44, 48, 53, 57, 61, 68, 72, 76, 80, 85, 89, 93, 97, 104, 108, 112, 116, 120, 125, 129, 133, 137, 141, 148, 152, 156, 160, 164, 168, 173, 177, 181, 185, 189, 193, 200, 204, 208, 212, 216, 220, 224, 229, 233, 237, 241, 245, 249, 253, 260, 264, 268, 272, 276, 280 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A071797(a(n)) = 4*m, A053186(a(n)+1) = 4*m, m > 0.
Apparently a bisection of A079896. While it may not be difficult to prove that the sequence is a subsequence of A079896, the apparent fact that a(n) = A079896(2n-1) is by no means obvious.
LINKS
EXAMPLE
8 - 2^2 = 1*4 and 24 - 4^2 = 2*4 so 8 and 24 are in the sequence.
MATHEMATICA
lsm4Q[n_]:=Module[{s=Floor[Sqrt[n]]^2}, s<n&&Divisible[n-s, 4]]; Select[ Range[300], lsm4Q] (* Harvey P. Dale, Jun 20 2014 *)
PROG
(PARI) is(n)=(n-sqrtint(n-1)^2)%4==0
CROSSREFS
Sequence in context: A030782 A219721 A176209 * A266212 A063849 A273980
KEYWORD
nonn
AUTHOR
Ralf Stephan, Sep 22 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 20 05:29 EDT 2024. Contains 373512 sequences. (Running on oeis4.)