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 A093153 Difference between counts of odd composites in A093151 and A093152 [Count (1 mod 4) - count (3 mod 4)]. 3

%I

%S 0,1,6,9,24,146,217,445,550,5959,14251,63336,118471,183456,951699,

%T 3458333,6284059,2581690,80743227,259753424

%N Difference between counts of odd composites in A093151 and A093152 [Count (1 mod 4) - count (3 mod 4)].

%C In A091295 the counts are 1 higher. I computed the differences through 10^8 and the rest by extrapolating from A091098 and A091099. In the ranges given, the counts of odd composites less than 10^n are higher 1 mod 4 than 3 mod 4. They are exactly opposite for the primes less than 10^n where 3 mod 4 is higher.

%F Subtract count of odd composites 3 mod 4 less than 10^n from those 1 mod 4

%F a(n) = A093151(n) - A093152(n). For n>1, a(n) = A091099(n) - A091098(n) - 1. [From _Max Alekseyev_, May 17 2009]

%e Below 10^3 there are 169 odd composites 1 mod 4 and 163 odd composites 3 mod 4, so a(3)=169-163=6

%Y Cf. A093151 A093152 A091295 A091098 A091099.

%K more,nonn

%O 1,3

%A _Enoch Haga_, Mar 24 2004

%E More terms from _Max Alekseyev_, May 17 2009

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Last modified July 29 01:22 EDT 2021. Contains 346340 sequences. (Running on oeis4.)