A067474 Smallest n-digit square starting with 4.

4, 49, 400, 4096, 40000, 400689, 4000000, 40005625, 400000000, 4000056516, 40000000000, 400000591936, 4000000000000, 40000008597136, 400000000000000, 4000000100766916, 40000000000000000, 400000001222314089, 4000000000000000000, 40000000008389413041

Offset: 1

Author

Amarnath Murthy, Feb 09 2002

Keywords

• nonn
• base
• easy

Crossrefs

Cf. A000290, A035071 (roots), A045787, A067479 (2..9).

Programs

Mathematica

nS[n_] := Module[{i = Floor[Sqrt[n]]}, If[i^2==n, i^2, (i + 1)^2]]; Table[nS[4 10^i], {i, 0, 25}]

PARI

for(n=1,20,a=ceil(sqrt(4*10^(n-1)))^2; print(a))

Formula

a(n) = ceiling(sqrt(4*10^(n-1)))^2. - Rick L. Shepherd, Feb 18 2002

Extensions

More terms from Rick L. Shepherd, Feb 18 2002