cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A169912 Number of irreducible Boolean polynomials of degree n.

Original entry on oeis.org

1, 2, 1, 3, 5, 9, 19, 39, 77, 168, 323, 682, 1424, 2902, 5956, 12368, 25329, 51866, 106427, 217216, 442313, 902921, 1833029, 3719745, 7548521, 15264350, 30859444, 62355854, 125773168, 253461052, 510471015, 1027067090, 2065390101, 4151081457, 8336751732, 16734781946, 33583213577, 67357328359, 135056786787
Offset: 0

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Let B be the Boolean ring {0,1} with 0+0=0, 0+1=1+1=1, 0*0=0*1=0, 1*1=1 (0 = FALSE, 1 = TRUE, + = OR, * = AND); then a(n) = number of irreducible elements of degree n in the polynomial ring B[X].

Examples

			a(0) = 1: 1.
a(1) = 2: X and X+1.
a(2) = 1: X^2+1 (note that X^2+X+1 = (X+1)^2 is reducible).
a(3) = 3: X^3+1, X^3+X+1, X^3+X^2+1.
		

Crossrefs

Formula

a(n) + A169913(n) = 2^n.

Extensions

More terms from David Applegate, Jul 19 2010

A169913 Number of reducible Boolean polynomials of degree n.

Original entry on oeis.org

0, 0, 3, 5, 11, 23, 45, 89, 179, 344, 701, 1366, 2672, 5290, 10428, 20400, 40207, 79206, 155717, 307072, 606263, 1194231, 2361275, 4668863, 9228695, 18290082, 36249420, 71861874, 142662288, 283409860, 563270809, 1120416558, 2229577195, 4438853135, 8843117452, 17624956422, 35136263159, 70081625113, 139821120157
Offset: 0

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Keywords

Comments

See A169912 for details.

Crossrefs

Extensions

More terms from David Applegate, Jul 19 2010
Showing 1-2 of 2 results.