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!)
 A066788 a(n) = gcd(phi(n), n^2 + 1). 1
 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 5, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 10, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 5, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 10, 1, 2, 1, 2, 5, 2, 1, 2, 1, 2, 5, 2, 1, 2, 1, 10, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Harry J. Smith, Table of n, a(n) for n = 1..1000 MATHEMATICA Table[GCD[EulerPhi[n], n^2+1], {n, 110}] (* Harvey P. Dale, Feb 14 2018 *) PROG (PARI) { for (n=1, 1000, write("b066788.txt", n, " ", gcd( eulerphi(n), n^2 + 1)) ) } \\ Harry J. Smith, Mar 26 2010 CROSSREFS Sequence in context: A347516 A322357 A160989 * A160988 A184319 A160987 Adjacent sequences:  A066785 A066786 A066787 * A066789 A066790 A066791 KEYWORD nonn 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 November 30 12:28 EST 2021. Contains 349419 sequences. (Running on oeis4.)