A053285 -id:A053285 - cp's OEIS frontend

A096856 a(n) = A062402(2^n+1).

1, 3, 7, 12, 31, 42, 124, 224, 511, 847, 1953, 2688, 12264, 18816, 29127, 72540, 131071, 195048, 558523, 1077440, 3164112, 4552020, 10890040, 10342080, 54525848, 73260781, 155671040, 318848400, 1080311232, 964580240, 3070642080, 4340711424, 13722819600, 19039027200

Offset: 0

Labos Elemer, Jul 19 2004

nonn

Amiram Eldar, Table of n, a(n) for n = 0..372

Cf. A000203, A053285, A062401, A062402, A053287, A096853, A096854, A096855.

Table[DivisorSigma[1, EulerPhi[2^n + 1]], {n, 0, 30}]

a(n) = A000203(A053285(n)). - Amiram Eldar, Jun 04 2024

Offset changed to 0, a(0) prepended and three more terms added by Amiram Eldar, Jun 04 2024

A069925 a(n) = phi(2^n+1)/(2*n).

Original entry on oeis.org

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

Offset: 1

Benoit Cloitre, Apr 25 2002

Number of primitive self-reciprocal polynomials of degree 2*n over GF(2). - Joerg Arndt, Jul 04 2012

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.

Cf. A011260 (degree-n primitive polynomials).
Cf. A000048 (degree-2*n irreducible self-reciprocal polynomials).
Cf. A000010, A000051, A053285.

Table[EulerPhi[2^n+1]/(2n),{n,50}] (* Harvey P. Dale, Nov 15 2011 *)

a(n) = eulerphi(2^n+1)/(2*n); /* Joerg Arndt, Jul 04 2012 */

a(n) = phi(2^n+1)/(2*n).

a(n) = A053285(n)/(2*n). - Amiram Eldar, Jun 02 2022

cp's OEIS Frontend

A096856 a(n) = A062402(2^n+1).

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