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%I #8 Dec 05 2013 19:56:01
%S 1,1,3,1,2,3,1,3,5,7,1,2,3,5,19,1,3,5,7,13,19,1,2,3,5,7,11,13,1,3,5,7,
%T 11,13,17,23,1,2,3,5,7,11,13,17,31,1,3,5,7,11,13,17,19,23,31,1,2,3,5,
%U 7,11,13,17,19,23,31,1,3,5,7,11,13,17,19,23,29,41,47,1,2,3,5,7,11,13,17
%N Triangle read by rows in which the n-th row contains the smallest set of n coprime numbers with a sum which is a multiple of n.
%C In the row for 6 the fifth term is 13 and not 11 as this forces the sixth term divisible by (not coprime to 3) 3. For even n all the terms have to be odd. This sequence set should exhibit some interesting properties and needs attention.
%H Franklin T. Adams-Watters, <a href="/A081485/b081485.txt">Rows n=1..80 of triangle, flattened</a>
%e Triangle begins
%e 1
%e 1 3
%e 1 2 3
%e 1 3 5 7
%e 1 2 3 5 19
%e 1 3 5 7 13 19
%o Contribution from _Franklin T. Adams-Watters_, Apr 09 2009: (Start)
%o (PARI) arow(n) = {local(v, t, p, r);
%o if(n<=3,return(if(n==2,[1,3],if(n==3,[1,2,3],[1]))));
%o v=vector(n);v[1]=1;v[2]=if(n%2==0,3,2);t=v[2]+1;
%o for(i=3,n-2,v[i]=nextprime(v[i-1]+1);t+=v[i]);
%o p=nextprime(v[n-2]+1);
%o while(gcd(t+p,n)>1,p=nextprime(p+1));
%o v[n-1]=p;t+=p;r=p\n*n-t%n;
%o while(r<=p,r+=n);
%o while(!isprime(r),r+=n);
%o v[n]=r;v} (End)
%Y Cf. A081486, A081487, A081488.
%K nonn,tabl
%O 1,3
%A _Amarnath Murthy_, Mar 24 2003
%E Corrected and extended by _David Wasserman_, Jun 03 2004
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