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A281015
Numbers with a prime number of dots in their International Morse numeral representation.
5
2, 3, 5, 7, 8, 11, 12, 14, 16, 18, 19, 20, 21, 23, 25, 27, 29, 30, 32, 34, 36, 38, 41, 43, 47, 49, 50, 52, 58, 61, 63, 67, 69, 70, 72, 74, 76, 78, 80, 81, 83, 85, 87, 89, 91, 92, 94, 96, 98, 99, 101, 102, 104, 106, 108, 109, 110, 111, 113, 115, 117, 119, 120, 122, 124, 126
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
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
(Python) # uses[A280913]
from sympy import isprime
i=0
j=1
while j<=100:
if isprime(A280913(i)):
print(str(j)+" "+str(i))
j+=1
i+=1
(PARI) select( {is_A281015(n)=isprime(A280913(n))}, [0..150]) \\ M. F. Hasler, Jun 22 2020
CROSSREFS
Cf. A060109 (Morse code for n), A280913 (number of dots in Morse code for n).
Cf. A281017 (same for dashes), A281018 (intersection of the two).
Sequence in context: A284655 A083028 A370867 * A288625 A189168 A182799
KEYWORD
nonn,base
AUTHOR
Indranil Ghosh, Jan 13 2017
STATUS
approved