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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A249305 Primes p such that 2^p - p^2 is not squarefree. 0
 2, 89, 149, 151, 383, 409, 443 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sequence is infinite, containing all primes congruent to 2, 4, 89, or 115 mod 147. - Charles R Greathouse IV, Oct 28 2014 997 is also a term in this sequence. - Kevin P. Thompson, Jun 13 2022 LINKS Table of n, a(n) for n=1..7. FORMULA a(n) < (21 + e)*n log n for any e > 0 and all large enough n. - Charles R Greathouse IV, Oct 28 2014 EXAMPLE 2 is in this sequence because 2 is prime and 2^2 - 2^2 = 0 is not squarefree. PROG (Magma) [n: n in [3..269] | IsPrime(n) and not IsSquarefree(2^n - n^2)]; (PARI) is(n)=isprime(n) && !issquarefree(2^n-n^2) \\ Charles R Greathouse IV, Oct 28 2014 CROSSREFS Cf. A005117, A024012. Sequence in context: A139881 A161676 A235467 * A023302 A041967 A226768 Adjacent sequences: A249302 A249303 A249304 * A249306 A249307 A249308 KEYWORD nonn,more AUTHOR Juri-Stepan Gerasimov, Oct 25 2014 EXTENSIONS a(5)-a(6) from Charles R Greathouse IV, Oct 28 2014 a(7) from Kevin P. Thompson, Jun 13 2022 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.

Last modified July 18 13:34 EDT 2024. Contains 374378 sequences. (Running on oeis4.)