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 A019462 #17 Oct 24 2024 16:18:25
%S A019462 3,4,4,6,12,15,45,49,196,201,1005,1011,6066,6073,42511,42519,340152,
%T A019462 340161,3061449,3061459,30614590,30614601,336760611,336760623,
%U A019462 4041127476,4041127489,52534657357,52534657371,735485203194,735485203209,11032278048135,11032278048151
%N A019462 Add 1, multiply by 1, add 2, multiply by 2, etc., start with 3.
%H A019462 Paolo Xausa, <a href="/A019462/b019462.txt">Table of n, a(n) for n = 0..800</a>
%H A019462 Nick Hobson, <a href="/A019462/a019462.py.txt">Python program for this sequence</a>
%t A019462 Module[{a = 3}, Flatten[{a, Array[{a += #, a *= #} &, 20]}]] (* _Paolo Xausa_, Oct 24 2024 *)
%o A019462 (PARI) A019462(n, a=3)={for(i=2, n+1, if(bittest(i, 0), a*=i\2, a+=i\2)); a} \\ _M. F. Hasler_, Feb 25 2018
%Y A019462 Cf. A019461 (same, but start with 0), A019463 (start with 1), A019460 (start with 2), A082448 (start with 4).
%Y A019462 Cf. A082458, A019464 .. A019466 (similar, but first multiply, then add).
%K A019462 nonn
%O A019462 0,1
%A A019462 _N. J. A. Sloane_
%E A019462 Edited by _M. F. Hasler_, Feb 25 2018