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%I #9 Dec 19 2017 14:38:45
%S 58,61,98,138,193,217,222,233,253,266,338,358,373,393,398,402,453,461,
%T 466,477,481,542,553,557,586,597,602,618,633,646,662,761,822,838,853,
%U 857,877,898,901,913,918,926,941,986,1006,1041,1061,1077,1126,1157,1161
%N Numbers n such that T(n)+10 is the next prime after T(n), where T(n) = A000217(n).
%H Harvey P. Dale, <a href="/A129546/b129546.txt">Table of n, a(n) for n = 1..1000</a>
%e T(58)=1711 and 1711+10=1721 is the least prime > 1711;
%e T(61)=1891 and 1891+10=1901 is the least prime > 1891.
%t nptQ[n_]:=Module[{tr=(n(n+1))/2},NextPrime[tr]-tr==10]; Select[ Range[ 1200], nptQ] (* _Harvey P. Dale_, Dec 19 2017 *)
%o (PARI) isok(n) = t = n*(n+1)/2; nextprime(t+1) == (t + 10); \\ _Michel Marcus_, Oct 13 2013
%Y Cf. A000217, A129755, A130178.
%K nonn
%O 1,1
%A _Zak Seidov_, May 30 2007