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%I #19 Jan 19 2019 04:14:58
%S 1,2,1,2,3,4,5,1,2,6,3,4,7,8,5,9,1,2,10,6,3,4,11,7,8,5,12,13,9,1,2,14,
%T 10,6,3,4,15,16,17,11,7,8,5,18,19,20,12,13,9,1,2,21,22,23,14,24,10,6,
%U 3,4,25,26,15,27,16,28,17,11,7,8,5,29,18,30,19,20,12,13,9,1,2,31,21,22,32
%N A fractal sequence. Underline the first occurrence of "1", then the first occurrence of "2", the first "3", etc. The non-underlined terms are the sequence itself.
%C For all [a,b,c] triples of consecutive terms where (a+b) is prime, do underline c. The non-underlined terms are the sequence itself.
%H M. F. Hasler, <a href="/A133182/b133182.txt">Table of n, a(n) for n = 1..14868</a>.
%H Eric Angelini, <a href="http://www.cetteadressecomportecinquantesignes.com/FracPrimSums.htm">A fractal sequence with prime sums</a>
%H Eric Angelini, <a href="/A133182/a133182.pdf">A fractal sequence with prime sums</a> [Cached copy, with permission. Pdf file only, no color]
%o (PARI) A133182(find=2007,show=1,a=[1,2],no=0,ni=2)={ while(a[ #a]!=find,a=concat(a,if(isprime(a[ #a]+a[ #a-1]),no++,a[ni++ ]))); if(show,a,#a)} /* use A133182(N) to get all terms up to first occurrence of N ; A133182(N,0) to get only the index of that term */ \\ _M. F. Hasler_, Oct 17 2007
%K nonn,look
%O 1,2
%A _Eric Angelini_, Oct 11 2007
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