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A053674 Least number coprime to n, n+1, n+2, n+3, n+4 and n+5. 13

%I

%S 7,11,11,11,11,13,13,7,17,17,17,11,11,11,7,11,13,13,13,13,17,7,11,11,

%T 11,11,11,13,7,13,13,13,13,11,11,7,11,11,17,13,13,13,7,13,11,11,11,11,

%U 11,7,19,17,13,13,13,11,7,11,11,11,17,17,19,7,19,13,11,11,11,11,7,13

%N Least number coprime to n, n+1, n+2, n+3, n+4 and n+5.

%C All terms are primes greater than 5. Records: a(1) = 7, a(2) = 11, a(6) = 13, a(9) = 17, a(51) = 19, a(151) = 23, a(437) = 29, a(779) = 31, a(1766) = 37, a(60605) = 41, a(324596) = 43, a(3555107) = 47, a(14511250) = 53, a(65209022) = 59, a(764050703) = 61, .... - _Charles R Greathouse IV_, Feb 07 2017

%H Reinhard Zumkeller, <a href="/A053674/b053674.txt">Table of n, a(n) for n = 1..10000</a>

%t a[n_] := (k = 7; While[ ! And @@ (CoprimeQ[k, #] & ) /@ Range[n, n+5], k++]; k); Table[a[n], {n, 1, 72}] (* _Jean-Fran├žois Alcover_, Nov 30 2011 *)

%o (Haskell)

%o import Data.List (elemIndex)

%o import Data.Maybe (fromJust)

%o a053674 n = 2 + fromJust

%o (elemIndex 1 $ map (gcd $ foldl1 lcm $ take 6 [n..]) [2..])

%o -- _Reinhard Zumkeller_, Sep 25 2011

%o (PARI) a(n)=my(L=lcm([n..n+5])); forprime(p=7,, if(L%p, return(p))) \\ _Charles R Greathouse IV_, Feb 07 2017

%Y Cf. A053669-A053673.

%K nonn,easy,nice

%O 1,1

%A _Henry Bottomley_, Feb 15 2000

%E More terms from Andrew Gacek (andrew(AT)dgi.net), Feb 21 2000 and _James A. Sellers_, Feb 22 2000

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Last modified April 24 22:26 EDT 2019. Contains 322446 sequences. (Running on oeis4.)