%I A055266
%S A055266 1,3,5,4,2,6,8,7,9,11,10,12,13,14,16,17,15,18,20,19,21,23,22,24,25,26,
%T A055266 28,27,29,31,32,30,33,35,34,36,38,37,39,41,40,42,43,44,46,45,47,48,50,
%U A055266 49,51,53,52,54,56,55,57,58,59,60,61,62,63,65,64,66,67,68,70,71,69,72
%N A055266 Smallest positive integer not already in sequence with a(n)+a(n-1) not 
               prime.
%H A055266 <a href="Sindx_Per.html#IntegerPermutation">Index entries for sequences 
               that are permutations of the natural numbers</a>
%e A055266 a(3)=5 because 1 and 3 have already been used and both 3+2=5 and 3+4=7 
               are prime while 3+5=8 is not prime.
%t A055266 f[ s_ ]:=Block[ {k=1,a=s[ [ -1 ] ]},While[ Or[ MemberQ[ s,k ],PrimeQ[ 
               a+k ] ],k++ ];Append[ s,k ] ];Nest[ f,{1},121 ] [ From Zak Seidov 
               (zakseidov(AT)yahoo.com), Oct 21 2009 ]
%Y A055266 Cf. A055265.
%Y A055266 Sequence in context: A073006 A165109 A134892 this_sequence A075077 A081361 
               A086181
%Y A055266 Adjacent sequences: A055263 A055264 A055265 this_sequence A055267 A055268 
               A055269
%K A055266 easy,nonn
%O A055266 1,2
%A A055266 Henry Bottomley (se16(AT)btinternet.com), May 09 2000
%E A055266 Corrected by Zak Seidov (zakseidov(AT)yahoo.com), Oct 21 2009