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 A071825 (Number of x with largest prime factor of the form 4k+3 less than or equal to n) minus (Number of x with largest prime factor of the form 4k+1 less than or equal to n). 0
 0, 1, 1, 0, 1, 2, 2, 3, 2, 3, 4, 3, 4, 3, 3, 2, 3, 4, 3, 4, 5, 6, 7, 6, 5, 6, 7, 6, 5, 6, 6, 7, 6, 7, 8, 7, 8, 7, 6, 5, 6, 7, 8, 7, 8, 9, 10, 11, 10, 9, 8, 7, 8, 9, 10, 11, 10, 11, 10, 9, 10, 11, 11, 10, 11, 12, 11, 12, 13, 14, 15, 14, 13, 12, 13, 14, 13, 14, 13, 14, 13, 14, 15, 14, 15, 14, 15 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS Weak conjecture: sequence gives positive values only; strong conjecture: for n large enough a(n) > 2*sqrt(n). LINKS FORMULA a(n) = Card( x<=n : A006530(x) == 3 mod 4) - Card( x<=n : A006530(x) == 1 mod 4) PROG (PARI) for(n=2, 200, print1(sum(i=2, n, if((component(component(factor(i), 1), omega(i))-3)%4, 0, 1))-sum(i=2, n, if((component(component(factor(i), 1), omega(i))-1)%4, 0, 1)), ", ")) CROSSREFS Sequence in context: A147952 A091316 A321862 * A115727 A115726 A086413 Adjacent sequences: A071822 A071823 A071824 * A071826 A071827 A071828 KEYWORD easy,nonn AUTHOR Benoit Cloitre, Jun 07 2002 STATUS approved

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Last modified January 31 01:17 EST 2023. Contains 359947 sequences. (Running on oeis4.)