A091214 - OEIS

This site is supported by donations to The OEIS Foundation.

A091214

Number of irreducible GF(2)[X]-polynomials that are composite integers.

25, 55, 87, 91, 115, 117, 143, 145, 171, 185, 203, 213, 247, 253, 285, 299, 301, 319, 333, 351, 355, 357, 361, 369, 375, 391, 395, 415, 425, 445, 451, 471, 477, 501, 505, 515, 529, 535, 539, 545, 623, 637, 665, 675, 687, 695, 721, 731, 789, 799, 803, 817 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	LINKS	`A. Karttunen, Scheme-program for computing this sequence.` `Index entries for sequences operating on GF(2)[X]-polynomials`
	MATHEMATICA	`fQ[n_] := Block[{ply = Plus @@ (Reverse@ IntegerDigits[n, 2] x^Range[0, Floor@ Log2@ n])}, ply == Factor[ply, Modulus -> 2] && n != 2^Floor@ Log2@ n && ! PrimeQ@ n]; Select[ Range@ 840, fQ] (* Robert G. Wilson v, Aug 12 2011 *)`
	CROSSREFS	`a(n) = A014580(A091215(n)). Intersection of A002808 and A014580.` `Sequence in context: A176275 A108166 A080863 * A036305 A125827 A163654` `Adjacent sequences: A091211 A091212 A091213 * A091215 A091216 A091217`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen (His-Firstname.His-Surname(AT)iki.fi), Jan 03 2004`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 07:42 EST 2012. Contains 205717 sequences.