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A323049 Numbers that are neither 5-smooth nor a sum of two 5-smooth numbers.

%I A323049 #20 Apr 02 2019 12:44:39
%S A323049 71,119,142,191,211,213,223,238,239,284,299,311,319,355,357,359,367,
%T A323049 373,382,397,419,422,426,431,446,461,463,467,473,476,478,479,497,523,
%U A323049 529,547,551,553,559,568,569,571,573,583,589,595,598,599,607,613,617,619,622,623,638,639,659,669,671,703,709,710,713,714
%N A323049 Numbers that are neither 5-smooth nor a sum of two 5-smooth numbers.
%C A323049 Complementary set of (A323048).
%C A323049 Also numbers k such that at least three five-smooth numbers are needed to sum to k. - _David A. Corneth_, Jan 04 2019
%C A323049 Contains all k == 71 or 119 (mod 120). - _Robert Israel_, Apr 02 2019
%H A323049 Robert Israel, <a href="/A323049/b323049.txt">Table of n, a(n) for n = 1..10000</a>
%p A323049 N:= 1000: # to get all terms <= N
%p A323049 V:= {seq(seq(seq(2^a*3^b*5^c, a = 0 .. floor(log[2](N/3^b/5^c))),b = 0 .. floor(log[3](N/5^c))),c=0..floor(log[5](N)))}:
%p A323049 S:= {$1..N} minus V minus {seq(seq(V[i]+V[j],i=1..j),j=1..nops(V))}:
%p A323049 A:= sort(convert(S,list)): # _Robert Israel_, Apr 02 2019
%t A323049 f[n_] := Union@Flatten@Table[2^a*3^b*5^c, {a, 0, Log2[n]}, {b, 0, Log[3, n/2^a]}, {c, 0, Log[5, n/(2^a*3^b)]}]; b = Block[{nn = 800, s}, s = f[nn]; {0, 1}~Join~
%t A323049    Select[Union@Flatten@Outer[Plus, s, s], # <= nn &]];
%t A323049 Complement[Range[800], b]
%Y A323049 Cf. A003586, A051037, A323048.
%Y A323049 Similar to A323046 (for 3-smooth numbers).
%K A323049 nonn
%O A323049 1,1
%A A323049 _Carlos Alves_, Jan 03 2019