0,2

All 3 apart from 1 in position given by A001108 and 2 for n=24.

n=4 -> 4^3+3^3+2^3+1^3 = 64+27+8+1 = 100

n=5 -> 5^3+4^3+3^3+2^3+1^3 = 125+64+27+8+1 = 225

n=6 -> 6^3+5^3+4^3+3^3+2^3+1^3 = 216+125+64+27+8+1 = 441

P:=proc(n) local a, i, k, j, ok, x; for i from 1 by 1 to n do x:=1; ok:=1; while ok=1 do a:=0; k:=i; while k>0 do a:=a+k^x; k:=k-1; od; if (trunc(sqrt(a)))^2=a then print(x); ok:=0; else x:=x+1; fi; od; od; end: P(100);

Cf. A001108.

Sequence in context: A141605 A073139 A122845 this_sequence A102818 A010701 A122553

Adjacent sequences: A135200 A135201 A135202 this_sequence A135204 A135205 A135206

easy,nonn

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Nov 28 2007