A178909 Indices of perfect polynomials over GF(2).

1, 6, 36, 54, 120, 2470, 2640, 3144, 3780, 32640, 41280, 52632, 67184, 1098176, 1157904, 2147450880

Offset

1,2

Comments

Numbers k such that k = A178908(k); sum of divisors of k-th GF(2) polynomial is the polynomial itself.

a(17) > 5*10^9. - Amiram Eldar, Oct 28 2019

Links

Table of n, a(n) for n=1..16.

Prog

(PARI) isok(n) = my(s = vecsum(divisors(Mod(1, 2)*Pol(binary(n))))); subst(lift(s), x, 2) == n; \\ Michel Marcus, Jan 13 2019

Crossrefs

Cf. A178908, A091220, A000396, A178911.

Sequence in context: A132633 A372945 A047792 * A206982 A121026 A207694

Adjacent sequences: A178906 A178907 A178908 * A178910 A178911 A178912

Keyword

nonn,more

Author

Franklin T. Adams-Watters, Jun 22 2010

Extensions

a(14)-a(15) from Amiram Eldar, Jan 13 2019

a(16) from Amiram Eldar, Oct 28 2019

Status

approved