1,1

The Morse code is written in current ITU standard.

This sequence is the intersection of A281015 and A281017.

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

Wikipedia, Morse Code

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

(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

Cf. A280913, A280916, A281015, A281017.

Sequence in context: A032967 A111101 A281017 * A184860 A242655 A145489

Adjacent sequences: A281015 A281016 A281017 * A281019 A281020 A281021

nonn,base

Indranil Ghosh, Jan 13 2017

approved