OFFSET
1,4
COMMENTS
Number of primitive self-reciprocal polynomials of degree 2*n over GF(2). - Joerg Arndt, Jul 04 2012
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1090
Joerg Arndt, Matters Computational (The Fxtbook), section 40.8 "Self-reciprocal polynomials", pp. 846-848.
Helmut Meyn and Werner Götz, Self-reciprocal Polynomials Over Finite Fields, Séminaire Lotharingien de Combinatoire, B21d, pp. 82-90, 1989.
FORMULA
a(n) = phi(2^n+1)/(2*n).
a(n) = A053285(n)/(2*n). - Amiram Eldar, Jun 02 2022
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
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 25 2002
STATUS
approved