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

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!)
 A066787 a(n) = gcd(2^n + 1, n^2 + 1). 1
 1, 5, 1, 17, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 65, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 41, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 29, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 565, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n)=1 or a(n)=0 mod(5) or a(n) is a prime congruent to 1 mod(4). LINKS Harry J. Smith, Table of n, a(n) for n = 1..1000 MAPLE A066787:=n->gcd(2^n+1, n^2+1): seq(A066787(n), n=1..100); # Wesley Ivan Hurt, Jan 03 2016 MATHEMATICA Table[GCD[2^n + 1, n^2 + 1], {n, 100}] (* Wesley Ivan Hurt, Jan 03 2016 *) PROG (PARI) { for (n=1, 1000, write("b066787.txt", n, " ", gcd( 2^n + 1, n^2 + 1)) ) } \\ Harry J. Smith, Mar 25 2010 (MAGMA) [GCD(2^n+1, n^2+1) : n in [1..100]]; // Wesley Ivan Hurt, Jan 03 2016 CROSSREFS Sequence in context: A211808 A093826 A144699 * A058352 A121755 A104174 Adjacent sequences:  A066784 A066785 A066786 * A066788 A066789 A066790 KEYWORD nonn,easy AUTHOR Benoit Cloitre, Jan 18 2002 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 December 3 04:22 EST 2021. Contains 349445 sequences. (Running on oeis4.)