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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A089593 Numbers n such that n^2 + 2n + 2 is prime. 1
 0, 1, 3, 5, 9, 13, 15, 19, 23, 25, 35, 39, 53, 55, 65, 73, 83, 89, 93, 109, 115, 119, 123, 125, 129, 133, 145, 149, 155, 159, 169, 175, 179, 183, 203, 205, 209, 223, 229, 235, 239, 249, 255, 259, 263, 269, 279, 283, 299, 305, 313, 325, 339, 349 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 FORMULA a(n) = A005574(n)-1 = A090693(n)-2. MATHEMATICA (* Vincenzo Librandi, May 23 2014 *) PROG (MAGMA)[n: n in [0..400]|IsPrime(n^2+2*n+2)]; // Vincenzo Librandi, Dec 17 2010 (PARI) is(n)=isprime(n^2+2*n+2) \\ Charles R Greathouse IV, Jun 12 2017 CROSSREFS Cf. A002496 gives the primes, A005574, A090693. Sequence in context: A177078 A187906 A187229 * A204663 A191129 A018533 Adjacent sequences:  A089590 A089591 A089592 * A089594 A089595 A089596 KEYWORD nonn,easy AUTHOR Giovanni Teofilatto, Dec 30 2003 EXTENSIONS Corrected by Vincenzo Librandi, Dec 17 2010 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.

Last modified August 14 07:04 EDT 2020. Contains 336477 sequences. (Running on oeis4.)