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 A234002 4n/A234001(n). 1
 1, 1, 4, 4, 1, 1, 2, 4, 3, 1, 4, 4, 1, 1, 2, 8, 1, 3, 4, 4, 1, 1, 2, 4, 5, 1, 36, 4, 1, 1, 2, 16, 1, 1, 4, 12, 1, 1, 2, 4, 1, 1, 4, 4, 3, 1, 2, 8, 7, 5, 4, 4, 1, 9, 2, 4, 1, 1, 4, 4, 1, 1, 6, 32, 1, 1, 4, 4, 1, 1, 2, 12, 1, 1, 20, 4, 1, 1, 2, 8, 27, 1, 4, 4, 1, 1, 2, 4, 1, 3, 4, 4, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Please look into A234001 for a more detailed description. If n is squarefree and n == 1 (mod 4) or n == 2 (mod 4), then a(n) = 1. If p^2 divides n for some prime p, a(n) is a multiple of p. If n == 3 (mod 8), then a(n) is a multiple of 4 because numbers of the form x^2+n*y^2 cannot have any prime factors that are congruent to 2+n (mod 2n) raised to an odd power. If n == 7 (mod 8), then a(n) is a multiple of 2 because numbers of the form x^2+n*y^2 can have prime factors that are congruent to 2+n (mod 2n) raised to an odd power, but they cannot be congruent to 2 (mod 4). So, we need to characterize the prime factor of 2 from the remaining prime factors that are congruent to 2+n (mod 2n) separately. LINKS CROSSREFS Cf. A000926, A232550, A232551, A234001. Sequence in context: A307886 A351122 A214499 * A016496 A143253 A060036 Adjacent sequences: A233999 A234000 A234001 * A234003 A234004 A234005 KEYWORD nonn,uned AUTHOR V. Raman, Dec 18 2013 STATUS approved

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Last modified January 30 02:06 EST 2023. Contains 359939 sequences. (Running on oeis4.)