login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A281018 Numbers with both prime number of dots and prime number of dashes in their International Morse numeral representation. 1
2, 3, 7, 8, 12, 14, 16, 18, 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, 81, 83, 85, 87, 89, 92, 94, 96, 98, 101, 109, 110, 190, 200, 355, 445, 454, 456, 465, 535, 544, 546, 553, 557, 564, 566, 575, 645 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The Morse code is written in current ITU standard.

This sequence is the intersection of A281015 and A281017.

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..10000

Wikipedia, Morse Code

EXAMPLE

27 is in the sequence because it is both in A281015 and A281017.

PROG

(Python)

from sympy import isprime

i=0

j=1

while j<=10000:

    if isprime(A280913(i))==True and isprime(A280916(i))==True:

        print str(j)+" "+str(i)

        j+=1

    i+=1

CROSSREFS

Cf. A280913, A280916, A281015, A281017.

Sequence in context: A032967 A111101 A281017 * A184860 A242655 A145489

Adjacent sequences:  A281015 A281016 A281017 * A281019 A281020 A281021

KEYWORD

nonn,base

AUTHOR

Indranil Ghosh, Jan 13 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 18:03 EDT 2019. Contains 328102 sequences. (Running on oeis4.)