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 A051417 Quotients of consecutive values of lcm {1, 3, 5 ...,2n-1} or A025547(n+1)/A025547(n). 3

%I

%S 3,5,7,3,11,13,1,17,19,1,23,5,3,29,31,1,1,37,1,41,43,1,47,7,1,53,1,1,

%T 59,61,1,1,67,1,71,73,1,1,79,3,83,1,1,89,1,1,1,97,1,101,103,1,107,109,

%U 1,113,1,1,1,11,1,5,127,1,131,1,1,137,139,1,1,1,1,149,151,1,1,157,1,1

%N Quotients of consecutive values of lcm {1, 3, 5 ...,2n-1} or A025547(n+1)/A025547(n).

%C a(n)=GCD( C(2n+1,1),C(2n+2,2),...,C(3n,n) ) where C(n,k)=binomial(n,k). - _Benoit Cloitre_, Jan 31 2003

%C a(n) = greatest common divisor of entries of zigzag matrix Z(n), as defined in A088961. - _Reinhard Zumkeller_, Oct 25 2013

%H Reinhard Zumkeller, <a href="/A051417/b051417.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>

%F a(n) = cyclotomic(2*n+1, 1). - _Vladeta Jovovic_, Apr 05 2004

%e a(5) = A025547(6)/A025547(5) = 3465/315 = 11

%t Table[Cyclotomic[2n+1,1],{n,90}] (* _Harvey P. Dale_, Apr 02 2011 *)

%t #[[2]]/#[[1]]&/@Partition[Table[LCM@@Range[1,2n+1,2],{n,0,80}],2,1] (* _Harvey P. Dale_, Mar 04 2013 *)

%o a051417 n = a051417_list !! (n-1)

%o a051417_list = zipWith div (tail a025547_list) a025547_list

%o -- _Reinhard Zumkeller_, Oct 25 2013

%Y A025547.

%Y Cf. A020500.

%K easy,nice,nonn

%O 1,1

%A Asher Auel (asher.auel(AT)reed.edu)

%E More terms from _James A. Sellers_

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Last modified May 16 06:54 EDT 2021. Contains 343939 sequences. (Running on oeis4.)