OFFSET
1,2
COMMENTS
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
T(2)=3, 13 is prime, so 2 is a term;
T(13)=91, 191 is prime, so 13 is a term;
T(17)=153, 1153 is prime, so 17 is a term.
MATHEMATICA
Rest[Select[Range[600], PrimeQ[FromDigits[Join[{1}, IntegerDigits[(# (#+1))/2]]]]&]] (* Harvey P. Dale, Apr 15 2009 *)
trprQ[n_]:=Module[{tr=(n(n+1))/2}, PrimeQ[10^IntegerLength[tr]+tr]]; Select[ Range[ 500], trprQ] (* Harvey P. Dale, Aug 04 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 28 2009
EXTENSIONS
First term (1) prepended by Harvey P. Dale, Aug 04 2019
STATUS
approved