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 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

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