
EXAMPLE

75 = 1^2 + 5^2 + 7^2 = 5^2 + 5^2 + 5^2,
76 = 2^2 + 6^2 + 6^2,
77 = 2^2 + 3^2 + 8^2 = 4^2 + 5^2 + 6^2,
78 = 2^2 + 5^2 + 7^2.
These the first 4 consecutive numbers with the same smallest number of squares needed to represent, so a(4) = 75.


MATHEMATICA

A002828[n_] := Module[{s = SquaresR[Range[4], n]}, If[First[s] > 0, 1, Length[First[Split[s]]] + 1]]; Do[find = 0; k = 0; While[find == 0, k++; If[Length[Union[Table[A002828[j], {j, k, k + n  1}]]] == 1, find = 1; Print[k]]], {n, 1, 7}]
