A060360 - OEIS

%I #12 Mar 20 2018 06:54:34

%S 1,1,1,1,1,1,17,17,19,19,23,23,23,17,43,43,1,1,1,1,1,1,29,29,41,41,1,

%T 1,43,1,1,1,1,1,43,43,43,43,47,47,83,83,83,83,1,1,83,83,83,83,61,61,

%U 61,61,61,61,149,149,1,1,1,97,97,97,89,89,89,89,109,109

%N a(n) = k - (largest prime < k), where k = lcm(1..n).

%F a(n) = A049711(A003418(n)). - _Michel Marcus_, Mar 20 2018

%t lcmp[n_]:=Module[{c=LCM@@Range[n]},c-NextPrime[c,-1]]; Array[lcmp,80,3] (* _Harvey P. Dale_, Dec 22 2012 *)

%o (PARI) a(n) = my(lc = lcm([1..n])); lc - precprime(lc-1); \\ _Michel Marcus_, Mar 20 2018

%Y Cf. A003418, A049711.

%K nonn

%O 3,7

%A _N. J. A. Sloane_, Apr 01 2001