Is there a number,aside from 1,simultaneously triangular,squre,pentagonal number ?
that is, is there a $\displaystyle L=(3n^2-n)/2=(k^2+k)/2=m^2$
for some m,n,k are positive integers.
Is there a number,aside from 1,simultaneously triangular,squre,pentagonal number ?
that is, is there a $\displaystyle L=(3n^2-n)/2=(k^2+k)/2=m^2$
for some m,n,k are positive integers.