login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A241267 Numbers n such that 4*n^2 + 4*n + 653 is not prime. 1
18, 19, 21, 24, 28, 33, 39, 46, 54, 60, 61, 62, 63, 65, 67, 72, 73, 75, 81, 82, 84, 85, 86, 93, 95, 96, 100, 101, 103, 104, 105, 109, 110, 111, 112, 117, 121, 122, 123, 125, 130, 137, 138, 139, 141, 142, 143, 144, 147, 152, 153, 154, 159, 160, 161, 165, 166 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

19 is in this sequence because 4*19^2 + 4*19 + 653 = 2173 = 41*53.

MATHEMATICA

Select[Range[0, 250], ! PrimeQ[4 #^2 + 4 # + 653] &]

PROG

(MAGMA) [n: n in [0..250] | not IsPrime(4*n^2+4*n+653)];

CROSSREFS

Complement of A188459.

Sequence in context: A018823 A025144 A326540 * A241848 A146331 A308894

Adjacent sequences:  A241264 A241265 A241266 * A241268 A241269 A241270

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Apr 20 2014

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 9 05:44 EST 2021. Contains 349627 sequences. (Running on oeis4.)