|
| |
|
|
A139401
|
|
If n is a square, a(n) is 0. Otherwise, a(n) is the smallest number k such that n is not a quadratic residue modulo k.
|
|
1
| |
|
|
0, 3, 4, 0, 3, 4, 4, 3, 0, 4, 3, 5, 5, 3, 4, 0, 3, 4, 4, 3, 8, 4, 3, 7, 0, 3, 4, 5, 3, 4, 4, 3, 5, 4, 3, 0, 5, 3, 4, 7, 3, 4, 4, 3, 7, 4, 3, 5, 0, 3, 4, 5, 3, 4, 4, 3, 5, 4, 3, 9, 7, 3, 4, 0, 3, 4, 4, 3, 7, 4, 3, 5, 5, 3, 4, 7, 3, 4, 4, 3, 0, 4, 3, 9, 8, 3, 4, 5, 3, 4, 4, 3, 5, 4, 3, 7, 5, 3, 4, 0, 3, 4, 4, 3, 9
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| I.e., if n is not a square, a(n) is the smallest number d for which a sequence that has a common difference of d contains n but that has no squares.
All nonzero values in this sequence are at least 3.
All nonzero values are prime powers, and every prime power except 2 appears in the sequence. This can be proved using the Chinese remainder theorem. - Franklin T. Adams-Watters, Jun 10 2011.
Records of nonzero values in this sequence are in A066730.
|
|
|
EXAMPLE
| a(2) = 3 because there are no squares in the sequence 2, 5, 8, 11, 14, 17, 20...
|
|
|
CROSSREFS
| Cf. A066730, A100867, A144294.
Sequence in context: A025278 A200514 A063405 * A110061 A021750 A197809
Adjacent sequences: A139398 A139399 A139400 * A139402 A139403 A139404
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| J. Lowell (jhbubby(AT)mindspring.com), Jun 09 2008, Jun 10 2008
|
|
|
EXTENSIONS
| More terms from John W. Layman (layman(AT)math.vt.edu), Jun 17 2008
New name from Franklin T. Adams-Watters, Jun 10 2011.
|
| |
|
|
