|
%I #24 Apr 04 2021 10:54:07
%S 4,4,4,4,6,6,8,8,9,10,12,12,14,14,15,16,18,18,20,20,21,22,24,24,25,26,
%T 27,28,30,30,32,32,33,34,35,36,38,38,39,40,42,42,44,44,45,46,48,48,49,
%U 50,51,52,54,54,55,56,57,58,60,60,62,62,63,64,65,66,68,68,69,70,72,72
%N a(n) is the smallest composite integer which is >= n.
%H Reinhard Zumkeller, <a href="/A113646/b113646.txt">Table of n, a(n) for n = 1..10000</a>
%F a(1) = a(2) = 4. For n >= 3, a(n) = A014683(n).
%p # This Maple program returns the smallest composite greater than n - _N. J. A. Sloane_, Sep 11 2019
%p iscomp := n-> if isprime(n) or (n=1) then false else true; fi;
%p f := proc(n) local a; global iscomp; a:=n+1; while not iscomp(a) do a:=a+1; od; a; end;
%t Table[k = n; While[! CompositeQ@ k, k++]; k, {n, 72}] (* _Michael De Vlieger_, Sep 06 2017 *)
%o (Haskell)
%o a113646 n = if n < 3 then 4 else a014683 n
%o -- _Reinhard Zumkeller_, Nov 01 2014
%o (Python)
%o from sympy import isprime
%o def a(n):
%o an = max(4, n)
%o while isprime(an): an += 1
%o return an
%o print([a(n) for n in range(1, 73)]) # _Michael S. Branicky_, Apr 04 2021
%Y Cf. A002808, A014683.
%K nonn
%O 1,1
%A _Leroy Quet_, Jan 15 2006
|
