|
|
A069925
|
|
a(n) = phi(2^n+1)/(2*n).
|
|
2
|
|
|
1, 1, 1, 2, 2, 4, 6, 16, 18, 40, 62, 160, 210, 448, 660, 2048, 2570, 5184, 9198, 24672, 32508, 76032, 121574, 344064, 405000, 1005888, 1569780, 4511520, 6066336, 12672000, 23091222, 67004160, 85342752, 200422656, 289531200, 892477440
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,4
|
|
COMMENTS
|
Number of primitive self-reciprocal polynomials of degree 2*n over GF(2). - Joerg Arndt, Jul 04 2012
|
|
LINKS
|
|
|
FORMULA
|
a(n) = phi(2^n+1)/(2*n).
|
|
MATHEMATICA
|
Table[EulerPhi[2^n+1]/(2n), {n, 50}] (* Harvey P. Dale, Nov 15 2011 *)
|
|
PROG
|
(PARI) a(n) = eulerphi(2^n+1)/(2*n); /* Joerg Arndt, Jul 04 2012 */
|
|
CROSSREFS
|
Cf. A011260 (degree-n primitive polynomials).
Cf. A000048 (degree-2*n irreducible self-reciprocal polynomials).
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|