This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A231735 Least positive k such that n*k^k - 1 is a prime, or 0 if no such k exists. 3
 2, 2, 1, 1, 2, 1, 1128, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS After the missing a(9) the sequence continues: 3, 2, 1, 6, 1, 2, 3, 2, 1, 6, 1, 2, 3, 14, 1. LINKS EXAMPLE Least k>0 such that 5*k^k-1 is a prime is k=2, so a(5)=2. CROSSREFS Cf. A000040, A193807, A231734. Sequence in context: A209332 A020945 A231734 * A016429 A131852 A139352 Adjacent sequences:  A231732 A231733 A231734 * A231736 A231737 A231738 KEYWORD nonn,hard,more AUTHOR Alex Ratushnyak, Nov 12 2013 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.