
is it 58......if yes then ..... desired values of N would be of the form n*(n+1)/2 such that it is a square of some number and to make it a square of a number v got to have an odd no. which is a square of some number and an even number such that its half is a square of some natural number...
1*2/2=1=1^2(N =1)
8*9/2=4*9=6^2(N=8)
49*50/2=49*25=35(N=49)
hence 49+1+8=58
