A105387 -id:A105387

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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.

+10
7

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, 76

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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

REFERENCES

"Learning the Radiotelegraph Code," Seventh Edition, published by American Radio Relay League, West Hartford 7, Connecticut, 1955.

"Morse Code Course," Jeppesen and Company, Denver, Colorado, 1962.

"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.

LINKS

Table of n, a(n) for n=1..26.

Wikipedia, Morse code.

EXAMPLE

The sixth letter, F, is ".._." in Morse. This becomes 1121 in ternary and 43 in decimal, so a(6) = 43.

PROG

(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

CROSSREFS

Cf. A060110, the same for numbers, and A060109, written in base 3.

Cf. A008777 (number of base 3 digits = dots and dashes in the n-th letter), A281015, A281017, A281018.

Cf. A105386, A105387 (ambiguous variants using digits 0 and 1).

KEYWORD

base,easy,fini,full,nonn,word

AUTHOR

Robert G. Wilson v, Feb 27 2001

EXTENSIONS

Edited, links and crossrefs added by M. F. Hasler, Jun 22 2020

STATUS

approved

A105386

Morse code alphabet where "." = 0 and "-" = 1, binary converted to decimal.

+10
3

1, 8, 10, 4, 0, 2, 6, 0, 0, 7, 5, 4, 3, 2, 7, 6, 13, 2, 0, 1, 1, 1, 3, 9, 11, 12

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Hamming weight A000120(a(n)) gives number of dashes in the Morse code of the n-th letter. A008777 allows us to know how many leading zeros a term should have. A059852 is a better (unambiguous) variant. - M. F. Hasler, Jun 23 2020

LINKS

Table of n, a(n) for n=1..26.

Omniglot, Morse Code

EXAMPLE

a(3) = 'C' = "-.-." -> 1010 (binary) = 10.

PROG

(PARI) A105386=[fromdigits([d-1|d<-digits(t, 3)], 2)|t<-A059852] \\ M. F. Hasler, Jun 23 2020

CROSSREFS

Cf. A105387, A059852 (Morse alphabet), A000120 (binary weight), A008777 (number of dots and dashes in Morse code for n-th letter).

KEYWORD

full,nonn,fini

AUTHOR

Bryan Jacobs (bryanjj(AT)gmail.com), Apr 02 2005

EXTENSIONS

Name and crossrefs edited by M. F. Hasler, Jun 23 2020

STATUS

approved

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