This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081329 #15 Jul 13 2023 01:51:51
%S A081329 1,23,46,47,53,61,69,71,77,79,92,94,95,101,103,106,107,115,119,121,
%T A081329 122,125,127,133,138,139,141,142,143,149,151,154,157,158,159,161,167,
%U A081329 169,173,175,179,181,183,184,185,187,188,190,191,197,199,202,203,205,206
%N A081329 Numbers having no representation as sum of two 3-smooth numbers.
%C A081329 Complement of A081330.
%H A081329 Amiram Eldar, <a href="/A081329/b081329.txt">Table of n, a(n) for n = 1..10000</a>
%F A081329 A081326(a(n)) = 0.
%e A081329 For all 3-smooth numbers m<23 the greatest prime factor of 23-m is >3: 23-1=2*11, 23-2=3*7, 23-3=4*5, 23-2^2=19, 23-2*3=17, 23-2^3=3*5, 23-3^2=2*7, 23-3*2^2=11, 23-2^4=7, 23-2*3^2=5, therefore 23 is a term.
%t A081329 max = 300; Complement[Range[max], Table[2^i*3^j + 2^k*3^l, {i, 0, Log[2, max] // Ceiling}, {j, 0, Log[3, max] // Ceiling}, {k, 0, Log[2, max] // Ceiling}, {l, 0, Log[3, max] // Ceiling}] // Flatten // Union // Select[#, # <= max& ]& ] (* _Jean-François Alcover_, Sep 10 2017 *)
%Y A081329 Cf. A003586, A081326, A081330.
%K A081329 nonn
%O A081329 1,2
%A A081329 _Reinhard Zumkeller_, Mar 19 2003