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A091247 Characteristic function of A091242: 1 if the n-th GF(2)[X] polynomial is reducible, 0 otherwise. 78
0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..101.

A. Karttunen, Scheme-program for computing this sequence.

Index entries for characteristic functions

Index entries for sequences operating on GF(2)[X]-polynomials

FORMULA

a(n) = A066247(A091203(n)) = A066247(A091205(n)).

PROG

(PARI) a(n) = if (n<2, 0, ! polisirreducible(Mod(1, 2)*Pol(binary(n)))); \\ Michel Marcus, Apr 12 2015

CROSSREFS

Cf. A066247, A091203, A091205, A091246.

Complementary to A091225. Partial sums give A091245.

Sequence in context: A087101 A000493 A011663 * A085137 A304577 A194670

Adjacent sequences:  A091244 A091245 A091246 * A091248 A091249 A091250

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 03 2004

STATUS

approved

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Last modified August 8 19:29 EDT 2020. Contains 336298 sequences. (Running on oeis4.)