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 A091222 Number of irreducible polynomials dividing n-th GF(2)[X]-polynomial, counted with multiplicity. 21
 0, 1, 1, 2, 2, 2, 1, 3, 2, 3, 1, 3, 1, 2, 3, 4, 4, 3, 1, 4, 2, 2, 2, 4, 1, 2, 3, 3, 2, 4, 1, 5, 2, 5, 2, 4, 1, 2, 3, 5, 1, 3, 2, 3, 4, 3, 1, 5, 2, 2, 5, 3, 2, 4, 1, 4, 3, 3, 1, 5, 1, 2, 3, 6, 4, 3, 1, 6, 2, 3, 2, 5, 1, 2, 4, 3, 2, 4, 2, 6, 2, 2, 3, 4, 6, 3, 1, 4, 2, 5, 1, 4, 2, 2, 3, 6, 1, 3, 3, 3, 3, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 A. Karttunen, Scheme-program for computing this sequence. FORMULA a(n) = A001222(A091203(n)) = A001222(A091205(n)). a(A000051(n)) = A091248(n). MAPLE for n from 1 to 1000 do   L:= convert(n, base, 2);   P:= add(L[i]*X^(i-1), i=1..nops(L));   R:= Factors(P) mod 2;   a[n]:= add(r[2], r=R[2]); od: seq(a[n], n=1..1000); # Robert Israel, Jun 07 2015 PROG (PARI) a(n)=my(fm=factor(Pol(binary(n))*Mod(1, 2))); sum(k=1, #fm~, fm[k, 2]) \\ Franklin T. Adams-Watters, Jun 07 2015 CROSSREFS Cf. A000051, A001222, A091203, A091205, A091248. Cf. A256170. Sequence in context: A260372 A037180 A241675 * A316506 A294884 A275024 Adjacent sequences:  A091219 A091220 A091221 * A091223 A091224 A091225 KEYWORD nonn AUTHOR Antti Karttunen, Jan 03 2004 STATUS approved

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Last modified January 22 16:45 EST 2019. Contains 319364 sequences. (Running on oeis4.)