A160109 Numbers k with the property that k^2 uses only nonsquare decimal digits (2,3,5,6,7,8).

5, 6, 15, 16, 24, 25, 26, 75, 76, 85, 94, 165, 166, 184, 194, 235, 256, 275, 475, 476, 485, 515, 516, 525, 526, 535, 594, 606, 615, 725, 734, 744, 765, 766, 816, 826, 856, 874, 875, 876, 885, 915, 924, 925, 934, 1524, 1525, 1526, 1535, 1624, 1635, 1665, 1666

Offset: 1

Author

Zak Seidov, May 02 2009

Keywords

• base
• nonn

Crossrefs

Cf. A077437 (Squares whose decimal digits are nonsquares (2, 3, 5, 6, 7, 8)).

Programs

Mathematica

nsdQ[n_]:=Module[{idn=IntegerDigits[n]}, !MemberQ[idn,1] && And@@SquareFreeQ/@idn]; Select[Range[2000],nsdQ[#^2]&]  (* Harvey P. Dale, Feb 01 2011 *)

Formula

a(n) = sqrt(A077437(n)).