Numbers k such that triangular(k) + triangular(2*k) is a square.

A224419

Numbers k such that triangular(k) + triangular(2*k) is a square.

Terms

    a(0) =0a(1) =1a(2) =25a(3) =216a(4) =1849a(5) =36481a(6) =311904a(7) =2666689a(8) =52606009a(9) =449765784a(10) =3845364121a(11) =75857828929a(12) =648561949056

External references