%I #2 Mar 30 2012 17:26:34

%S 2,19,23,61,107,229,233,271,317,397,401,439,443,523,569,607,653,691,

%T 821,859,863,1069,1283,1321,1367,1447,1451,1489,1493,1531,1619,1657,

%U 1787,1867,1871,1951,1997,2161,2207,2287,2333,2371,2417,2539,2543,2707,2711

%N a(n)>a(n-1), a(n) = smallest prime such that a(n)+a(n-1) is multiple of m, a(1)=2, m=21.

%C Cases m = 3, 5, 7, 9, 11, 13, 15, 17, 19, 21 in A175442-A175451.

%t a=2;s={a};k=2;m=21;Do[p=Prime[k];If[Mod[a+p,m]==0,a=p;AppendTo[s,a]];k++,{1000}];s

%Y Cf. A175442-A175450.

%K nonn

%O 1,1

%A _Zak Seidov_, May 16 2010