OFFSET
1,2
COMMENTS
Triangular numbers T(m)=m(m+1)/2 indices m of which are in A027861. T(m) such that m^2+(m+1)^2 is prime.
MAPLE
select(x-> isprime(4*x+1), [i*(i+1)/2$i=0..400])[]; # Alois P. Heinz, Feb 24 2024
MATHEMATICA
Select[Table[n(n+1)/2, {n, 0, 200}], PrimeQ[4#+1]&] (* Jean-François Alcover, Feb 24 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, May 26 2007
STATUS
approved