id:A046799 - OEIS Search Results

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Number of distinct prime factors of 2^n+1.

+0
4

1, 1, 1, 1, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 3, 3, 1, 2, 4, 2, 2, 3, 3, 2, 3, 4, 4, 3, 2, 3, 5, 2, 2, 4, 4, 5, 4, 3, 4, 3, 2, 3, 6, 2, 3, 5, 5, 3, 3, 3, 5, 5, 3, 3, 6, 5, 3, 4, 3, 4, 4, 2, 5, 5, 2, 6, 6, 3, 3, 4, 6, 3, 5, 3, 5, 6, 4, 6, 9, 2, 3, 6, 5, 6, 5, 4, 5, 4, 4, 4, 10, 6, 2, 4, 4, 5, 3, 5, 6, 7, 6, 2, 9, 3, 2 (list; graph; listen)

	OFFSET	`0,6`
	COMMENT	`The length of row n in A060444.`
	LINKS	`T. D. Noe, Table of n, a(n) for n=0..500`
	FORMULA	`a[ n ] = Length[ FactorInteger [ 2^n + 1 ] ]`
	EXAMPLE	`a[ 7 ]=129=3.43 has 2 prime factors`
	CROSSREFS	`A000051.` `Cf. A086257 (number of primitive prime factors)` `Sequence in context: A129139 A032539 A122922 this_sequence A037809 A097195 A129451` `Adjacent sequences: A046796 A046797 A046798 this_sequence A046800 A046801 A046802`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu)`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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