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%I #7 Dec 03 2024 12:47:09
%S 0,0,3,3,5,3,3,5,3,3,5,3,5,7,3,3,5,7,3,5,3,3,5,3,5,7,3,5,7,3,3,5,7,3,
%T 5,3,3,5,7,3,5,3,5,7,3,5,7,19,3,5,3,3,5,3,3,5,3,5,7,13,11,13,19,3,5,3,
%U 5,7,3,3,5,7,11,11,3,3,5,7,3,5,7,3,5,3,5,7,3,5,7,3,3,5,7,11,11,3,3,5
%N a(n) = 2*n mod q, where q is the greatest prime such that 2*n - q is also prime.
%t Table[Module[{p = 2, q},
%t While[True, q = 2 n - p; If[PrimeQ[p] && PrimeQ[q], Break[]];
%t p = NextPrime[p]]; Mod[2 n, q]], {n, 2, 100}]
%Y Cf. A002373.
%K nonn,new
%O 2,3
%A _Michel Eduardo Beleza Yamagishi_, Nov 19 2024