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 A059852 #23 Jun 07 2023 08:30:13
%S A059852 5,67,70,22,1,43,25,40,4,53,23,49,8,7,26,52,77,16,13,2,14,41,17,68,71,
%T A059852 76
%N A059852 Consider the English alphabet in Morse code (the International Morse radio telegraph code). Map a 'dit' to the digit one and a 'dah' to the digit 2, then express that ternary number in decimal.
%C A059852 Written in base 3, the terms read (12, 2111, 2121, 211, 1, 1121, 221, 1111, 11, 1222, 212, 1211, 22, 21, 222, 1221, 2212, 121, 111, 2, 112, 1112, 122, 2112, 2122, 2211). This contains all words over {1,2} with 1 to 4 letters except for 1122, 1212, 2221 and 2222, which correspond to the codes for Ü, Ä, Ö and CH. - _M. F. Hasler_, Jun 22 2020
%D A059852 "Learning the Radiotelegraph Code," Seventh Edition, published by American Radio Relay League, West Hartford 7, Connecticut, 1955.
%D A059852 "Morse Code Course," Jeppesen and Company, Denver, Colorado, 1962.
%D A059852 "International Morse Code," prepared by Lt. Commander F.R.L. Tuthill, USNR and Lt. (J.G.) E.L. Battey, USNR, published by Insuline Corporation of America, Long Island City, NY.
%H A059852 Wikipedia, <a href="http://en.wikipedia.org/wiki/Morse_code">Morse code</a>.
%e A059852 The sixth letter, F, is ".._." in Morse. This becomes 1121 in ternary and 43 in decimal, so a(6) = 43.
%o A059852 (PARI) A059852=digits(3008707498660932665486381130661318784490079420090,81) \\ or vecextract(apply(A032924,[1..28]), i) with i=numtoperm(26, 58849338891424664724588744) or i=vecsort(Vec("ETIANMSURWDKGOHVFuLaPJBXCYZQ"),,1)[1..26]. - _M. F. Hasler_, Jun 22 2020
%Y A059852 Cf. A060110, the same for numbers, and A060109, written in base 3.
%Y A059852 Cf. A008777 (number of base 3 digits = dots and dashes in the n-th letter), A281015, A281017, A281018.
%Y A059852 Cf. A105386, A105387 (ambiguous variants using digits 0 and 1).
%K A059852 base,easy,fini,full,nonn,word
%O A059852 1,1
%A A059852 _Robert G. Wilson v_, Feb 27 2001
%E A059852 Edited, links and crossrefs added by _M. F. Hasler_, Jun 22 2020