OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
T(58)=1711 and 1711+10=1721 is the least prime > 1711;
T(61)=1891 and 1891+10=1901 is the least prime > 1891.
MATHEMATICA
nptQ[n_]:=Module[{tr=(n(n+1))/2}, NextPrime[tr]-tr==10]; Select[ Range[ 1200], nptQ] (* Harvey P. Dale, Dec 19 2017 *)
PROG
(PARI) isok(n) = t = n*(n+1)/2; nextprime(t+1) == (t + 10); \\ Michel Marcus, Oct 13 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, May 30 2007
STATUS
approved