Largest n-digit triangular number whose external digits as well as internal digits form a triangular number, or 0 if no such number exists.

A077370

Largest n-digit triangular number whose external digits as well as internal digits form a triangular number, or 0 if no such number exists.

Terms

    a(0) =6a(1) =91a(2) =666a(3) =6786a(4) =48205a(5) =400065a(6) =2943951a(7) =56121715a(8) =497086215a(9) =5490000505a(10) =50127436765a(11) =401241809205

External references