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 A152259 #13 Jun 02 2025 01:14:02
%S A152259 3,5,9,11,13,21,25,35,37,43,45,69,73,85,89,131,133,139,141,163,165,
%T A152259 171,173,261,265,277,281,325,329,341,345,515,517,523,525,547,549,555,
%U A152259 557,643,645,651,653,675,677,683,685,1029,1033,1045,1049,1093,1097,1109,1113,1285,1289
%N A152259 Union of values: A147568(n) and 2*A147568(n) - 1.
%C A152259 Every even N>=6 is a sum of two terms of the sequence.
%H A152259 G. C. Greubel, <a href="/A152259/b152259.txt">Table of n, a(n) for n = 1..10000</a>
%t A152259 A000695[n_]:= FromDigits[IntegerDigits[n,2], 4];
%t A152259 Table[(3+(-1)^n)*A000695[Floor[(2*n-2-(-1)^n)/4]] +4+(-1)^n , {n, 202}]//DeleteDuplicates//Sort (* _G. C. Greubel_, May 22 2023 *)
%o A152259 (PARI) a147568(n) = 2*fromdigits(binary(n), 4) + 3;
%o A152259 lista(nn) = {my(v = vector(2*nn+2), ind = 0); for (n=0, nn, my(x = a147568(n)); v[ind++] = x; v[ind++] = 2*x - 1); vecsort(v,,8);} \\ _Michel Marcus_, Dec 18 2018
%Y A152259 Cf. A000695, A145812, A145819, A147568.
%K A152259 nonn
%O A152259 1,1
%A A152259 _Vladimir Shevelev_, Dec 01 2008
%E A152259 More terms from _Michel Marcus_, Dec 18 2018
%E A152259 Missing term 685 added by _G. C. Greubel_, May 22 2023