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Search: id:A070826
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%I A070826
%S A070826 1,3,15,105,1155,15015,255255,4849845,111546435,3234846615,
%T A070826 100280245065,3710369067405,152125131763605,6541380665835015,
%U A070826 307444891294245705,16294579238595022365,961380175077106319535
%N A070826 One half of product of first n primes A000040.
%C A070826 Identical with A002110(n)/2, n>=1.
%C A070826 a(n+1) is the least odd number with exactly n distinct prime divisors. 
               - Labos E. (labos(AT)ana.sote.hu), Mar 24 2003
%F A070826 a(n)=product(p(n), n=1..n) with p(n) := A000040(n).
%p A070826 with (numtheory):a:=n->mul(ithprime(j), j=2..n):seq(a(n), n=1..17); [From 
               Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 24 2008]
%t A070826 Rest[ FoldList[ Times, 1, Prime[ Range[ 18]] ]]/2 (from Robert G. Wilson 
               v Feb 17 2004)
%t A070826 FoldList[Times, 1, Prime[Range[2, 18]]] [From Zak Seidov (zakseidov(AT)yahoo.com), 
               Jan 26 2009]
%Y A070826 Cf. A003266 (for Fibonacci), A070825 (for Lucas), A003046 (for Catalan).
%Y A070826 Cf. also A091852.
%Y A070826 Sequence in context: A001147 A000268 A118750 this_sequence A048599 A129731 
               A088109
%Y A070826 Adjacent sequences: A070823 A070824 A070825 this_sequence A070827 A070828 
               A070829
%K A070826 nonn,easy
%O A070826 1,2
%A A070826 Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), May 10, 
               2002

    
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Last modified December 21 10:15 EST 2009. Contains 171081 sequences.


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