OFFSET
1,1
COMMENTS
The Morse code is written in current ITU standard.
Indices of primes in A280913. - M. F. Hasler, Jun 22 2020
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..10000
Wikipedia, Morse Code
EXAMPLE
27 is in the sequence because 27 in its Morse numeral representation is written as '..--- --...' which has 5 dots and 5 is prime.
PROG
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Indranil Ghosh, Jan 13 2017
STATUS
approved