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 A330247 #57 Aug 17 2021 02:47:36 %S A330247 16711680,16776960,16761035,65280,10494192,16753920,255 %N A330247 The decimal form of the n-th color mentioned in the song "I Can Sing a Rainbow". %C A330247 In this sequence the list of X11 color names (created at the Massachusetts Institute of Technology during the development of color-based computer display systems) has been used. In the X11 Color System, color codes are traditionally given in hexadecimal form RRGGBB to show the mix of red, green and blue required to form the color. In this sequence, the numbers have been converted into their decimal form so that, for example, pink, orange and blue are changed from ffc0cb, ffa500, 0000ff respectively to 16761035, 16753920, 255. %C A330247 The song "I Can Sing a Rainbow" was written by Arthur Hamilton and made famous when it was sung by Peggy Lee in the 1955 film "Pete Kelly's Blues". Although various artists have recorded the song over the years, sometimes altering the order of the colors, here the sequence sung by Peggy Lee is used, namely "red and yellow and pink and green, purple and orange and blue". %H A330247 N. J. A. Sloane and Chris Smith, <a href="/A330247/a330247.pdf">First three terms of A330247 presented graphically</a> %H A330247 Wikipedia, <a href="https://en.wikipedia.org/wiki/X11_color_names">X11 Color Names</a> %H A330247 <a href="/index/So#songs">Index entries for sequences related to songs</a> %e A330247 Red and yellow and pink and green %e A330247 Purple and orange and blue %e A330247 I can sing a rainbow %e A330247 Sing a rainbow %e A330247 Sing a rainbow too. %e A330247 | X11 Color | hexadecimal | decimal %e A330247 | System | color code | value = %e A330247 n | name | rrggbb | a(n) %e A330247 --+------------+--------------+--------- %e A330247 1 | red | ff0000 | 16711680 %e A330247 2 | yellow | ffff00 | 16776960 %e A330247 3 | pink | ffc0cb | 16761035 %e A330247 4 | green | 00ff00 | 65280 %e A330247 5 | purple | a020f0 | 10494192 %e A330247 6 | orange | ffa500 | 16753920 %e A330247 7 | blue | 0000ff | 255 %K A330247 base,fini,full,less,nonn %O A330247 1,1 %A A330247 _Chris Smith_, Dec 31 2019