A294882 Number of proper divisors of n that are not irreducible when their binary expansion is interpreted as polynomial over GF(2).

0, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 3, 1, 1, 2, 3, 1, 3, 1, 4, 1, 1, 1, 5, 2, 1, 2, 3, 1, 5, 1, 4, 1, 2, 2, 6, 1, 1, 1, 6, 1, 4, 1, 3, 4, 2, 1, 7, 1, 3, 2, 3, 1, 5, 2, 5, 1, 2, 1, 9, 1, 1, 3, 5, 2, 4, 1, 4, 2, 5, 1, 9, 1, 1, 3, 3, 1, 4, 1, 8, 3, 1, 1, 8, 3, 2, 2, 5, 1, 9, 1, 4, 1, 1, 2, 9, 1, 3, 3, 6, 1, 5, 1, 5, 5

Offset: 1

Author

Antti Karttunen, Nov 09 2017

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..21845
• Index entries for sequences related to polynomials in ring GF(2)[X]

Crossrefs

Cf. A032741, A091225, A294881, A294884.

Cf. also A234741, A234742, A294892.

Programs

PARI

A294882(n) = sumdiv(n,d,(d
				

Formula

a(n) = Sum_{d|n, dA091225(d)).

a(n) + A294881(n) = A032741(n).

For n > 1, a(n) = A294884(n) + A091225(n) - 1.