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 A158894 #22 Sep 01 2025 01:45:16
%S A158894 3,3,5,3,5,7,3,5,7,9,3,5,7,9,11,3,5,7,9,11,13,3,5,7,9,11,13,15,3,5,7,
%T A158894 9,11,13,15,17,3,5,7,9,11,13,15,17,19,3,5,7,9,11,13,15,17,19,21,3,5,7,
%U A158894 9,11,13,15,17,19,21,23,3,5,7,9,11,13,15,17,19
%N A158894 Sawtooth pattern of one, then two, then three, then four etc. consecutive odd numbers, starting each time at 3.
%C A158894 Obtained from A158405 by deleting the 1's, or from A141620 by deleting the positive numbers and flipping all signs.
%H A158894 Harvey P. Dale, <a href="/A158894/b158894.txt">Table of n, a(n) for n = 1..1000</a>
%F A158894 a(A000124(i))=3, i>=0. - _R. J. Mathar_, Apr 04 2009
%t A158894 sp[n_]:=Module[{cl=Range[3,51,2],l={}},Table[l=Join[l,Take[cl,i]], {i,n}];l ]; sp[15] (* _Harvey P. Dale_, Oct 30 2011 *)
%t A158894 Table[Range[3,2n+1,2],{n,15}]//Flatten (* _Harvey P. Dale_, Jun 27 2025 *)
%o A158894 (PARI) forstep(m=3,9,2,forstep(n=3,m,2,print1(n", "))) \\ _Charles R Greathouse IV_, Oct 30 2011
%Y A158894 Cf. A158405, A141620, A000124.
%K A158894 nonn,easy,changed
%O A158894 1,1
%A A158894 _Paul Curtz_, Mar 29 2009
%E A158894 Edited by _R. J. Mathar_, Apr 04 2009
%E A158894 Corrected by _Harvey P. Dale_, Oct 30 2011