|
Search: id:A002181
|
|
|
| A002181 |
|
Least k such that phi(k) = 2n, skipping impossibles.
(Formerly M2421 N0957)
|
|
+0
6
|
|
| 0, 3, 5, 7, 15, 11, 13, 17, 19, 25, 23, 35, 29, 31, 51, 37, 41, 43, 69, 47, 65, 53, 81, 87, 59, 61, 85, 67, 71, 73, 79, 123, 83, 129, 89, 141, 97, 101, 103, 159, 107, 109, 121, 113, 177, 143, 127, 255, 131, 161, 137, 139, 213, 185, 149, 151, 157, 187, 163, 249, 167, 203, 173
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Inverse of Euler totient function.
The first even integer occurs in the sequence for 2n = 2^32. The proof relies on the fifth Fermat number being composite. - Alain Jacques Ph.D. (alainjacques(AT)netspace.net.au), Jun 04 2006
A051445 without the zeros. The values of n are in A002180.
|
|
REFERENCES
|
J. W. L. Glaisher, Number-Divisor Tables. British Assoc. Math. Tables, Vol. 8, Camb. Univ. Press, 1940, p. 64.
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=0..4486
|
|
CROSSREFS
|
Cf. A058277, A006511.
Sequence in context: A024372 A061390 A051445 this_sequence A073692 A132012 A085494
Adjacent sequences: A002178 A002179 A002180 this_sequence A002182 A002183 A002184
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
Offset and initial term corrected Oct 07 2007
|
|
|
Search completed in 0.002 seconds
|
