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A294882
Number of proper divisors of n that are not irreducible when their binary expansion is interpreted as polynomial over GF(2).
5
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
1,8
FORMULA
a(n) = Sum_{d|n, d<n} (1-A091225(d)).
a(n) + A294881(n) = A032741(n).
For n > 1, a(n) = A294884(n) + A091225(n) - 1.
PROG
(PARI) A294882(n) = sumdiv(n, d, (d<n) * !polisirreducible(Mod(1, 2)*Pol(binary(d))));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 09 2017
STATUS
approved