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 A383622 #22 May 20 2025 10:21:57
%S A383622 1,4,5,7,11,13,14,17,19,20,23,25,28,29,31,35,37,41,43,44,46,47,49,52,
%T A383622 53,55,59,61,65,67,68,70,71,73,76,77,79,83,85,89,91,92,95,97,98,100,
%U A383622 101,103,107,109,113,115,116,119,121,124,125,127,131,133,137,139,140,143
%N A383622 First differences of A383621.
%C A383622 The multiplication table T(i,j) = A027649(i) * A007310(j) for i >= 0 and j >= 1, sorted in ascending order. There are repeating terms: 322 appears twice.
%H A383622 Yifan Xie, <a href="/A383622/b383622.txt">Table of n, a(n) for n = 1..10000</a>
%H A383622 Yifan Xie, <a href="/A383622/a383622_1.pdf">On a solvable minimal sum antichain problem</a>
%F A383622 a(n) ~ c*n, where c = 3*(Sum_{k=0..oo} 1/A027649(k))^(-1) = 2.216821...
%o A383622 (PARI) A027649(n) = 2*3^n-2^n;
%o A383622 upto(nn) = {v=[]; for(n=0, logint(nn,3), d = A027649(n); m = floor(nn/d); for(i=0, floor(m/6), if(6*i+1 <= m, v=concat(v, d*(6*i+1))); if(6*i+5 <= m, v=concat(v, d*(6*i+5))))); v=vecsort(v); v};
%Y A383622 Cf. A001047, A007310, A027649, A383621.
%K A383622 nonn,easy
%O A383622 1,2
%A A383622 _Yifan Xie_, May 10 2025