Search: id:A123133
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%I A123133
%S A123133 5,5,12,14,19,24,26,31,36,38,43,49,52,53,58,65,68,69,74,79,84,86,91,97,
%T A123133 100,101,106,111,115,120,122,127,131,137,138,142,149,152,153,158,163,
%U A123133 169,172,173,178,183,187,191,197,198,202,209,210,214,221,222,226,231
%N A123133 Sum of pairs of consecutive primes ( p(2n-1)+p(2n) ) and sum of pairs 
               of consecutive nonprime numbers ( np(2n-1)+np(2n) ) in order.
%H A123133 A. Frank & P. Jacqueroux, <a href="http://paulcooijmans.lunarpages.com/
               oth/intcontest.pdf">International Contest</a>, 2001. Item 13
%e A123133 a(1) = 1 + 4 = 5, a(2) = 2 + 3 = 5, a(3) = 5 + 7 = 12, a(4) = 6 + 8 = 
               14, a(5)= 9 + 10 = 19, a(6) = 11 + 13 = 24, a(7) = 12 + 14 = 26, 
               a(8) = 15 + 16 = 31,...
%o A123133 (PARI) nonprimenum=[]; for(n=1,200,if(!isprime(n),nonprimenum=concat(nonprimenum,
               n))); primenum=[]; forprime(n=1,200,primenum=concat(primenum,n)); 
               nonprimepair=[]; forstep(n=1,length(nonprimenum),2,nonprimepair=concat(nonprimepair,
               nonprimenum[n]+nonprimenum[n+1])); primepair=[]; forstep(n=1,length(primenum),
               2,primepair=concat(primepair,primenum[n]+primenum[n+1])); vecsort(concat(nonprimepair,
               primepair))
%Y A123133 Sequence in context: A164930 A098331 A061391 this_sequence A122213 A049735 
               A055526
%Y A123133 Adjacent sequences: A123130 A123131 A123132 this_sequence A123134 A123135 
               A123136
%K A123133 nonn
%O A123133 1,1
%A A123133 Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 30 2006

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