This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A125973 Smallest k such that k^n + k^(n-1) - 1 is prime. 10
 2, 2, 2, 2, 2, 3, 2, 2, 14, 4, 7, 2, 38, 6, 7, 3, 4, 10, 2, 9, 74, 6, 10, 7, 4, 61, 20, 4, 5, 9, 6, 16, 6, 8, 2, 9, 4, 10, 2, 48, 44, 163, 9, 2, 95, 3, 27, 70, 6, 26, 57, 9, 6, 8, 207, 2, 27, 15, 45, 7, 69, 199, 55, 16, 2, 5, 12, 43, 137, 39, 9, 57, 5, 20, 4, 115, 2, 103, 45, 15, 20, 109 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE Consider n = 6. k^6 + k^5 - 1 evaluates to 1, 95, 971 for k = 1, 2, 3. Only the last of these numbers is prime, hence a(6) = 3. PROG (PARI) {m=82; for(n=1, m, k=1; while(!isprime(k^n+k^(n-1)-1), k++); print1(k, ", "))} - Klaus Brockhaus, Dec 17 2006 CROSSREFS Cf. A000040, A045546, A125881-A125885, A125965-A125972, A126017. Sequence in context: A105068 A120676 A184172 * A189172 A001031 A035250 Adjacent sequences:  A125970 A125971 A125972 * A125974 A125975 A125976 KEYWORD nonn AUTHOR Artur Jasinski, Dec 14 2006 EXTENSIONS Edited and extended by Klaus Brockhaus, Dec 17 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .