OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
f:= proc(n) local m, p, q;
m:= n*(n+1)/2;
p:= prevprime(ceil(m/2));
q:= nextprime(p);
if p+q=m then p fi
end proc:
map(f, [$3..500]); # Robert Israel, May 04 2020
MATHEMATICA
tri[n_] := IntegerQ[Sqrt[1 + 8 n]]; t = {}; p1 = 2; While[Length[t] < 50, p2 = NextPrime[p1]; If[tri[p1 + p2], AppendTo[t, p1]]; p1 = p2]; t (* T. D. Noe, May 28 2013 *)
CROSSREFS
Cf. A175132 (numbers n such that sum of two consecutive primes is triangular(n)).
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, May 28 2013
STATUS
approved