A077676 Squares using only squarefree digits (2, 3, 5, 6, 7).

25, 36, 225, 256, 576, 625, 676, 5625, 5776, 7225, 27225, 27556, 37636, 55225, 65536, 75625, 225625, 226576, 235225, 265225, 266256, 275625, 276676, 367236, 525625, 553536, 732736, 765625, 767376, 2322576, 2325625, 2356225, 2637376, 2673225

Offset

1,1

Comments

a(n) is == 5 or 6 (mod 10).

Links

Harvey P. Dale, Table of n, a(n) for n = 1..600

Mathematica

sfdsQ[n_]:=Module[{idn=DigitCount[n]}, idn[[1]]==idn[[4]]==idn[[8]] == idn[[9]]==idn[[10]]==0]; Select[Range[2000]^2, sfdsQ] (* Harvey P. Dale, Oct 09 2011 *)
Table[Select[FromDigits/@Tuples[{2, 3, 5, 6, 7}, n], IntegerQ[Sqrt[#]]&], {n, 2, 7}]//Flatten (* Harvey P. Dale, Feb 04 2015 *)

Crossrefs

Cf. A077674, A077675, A006716. Different from A077437.

Sequence in context: A265211 A205644 A077437 * A030671 A030681 A167363

Adjacent sequences: A077673 A077674 A077675 * A077677 A077678 A077679

Keyword

base,nonn

Author

Amarnath Murthy, Nov 16 2002

Extensions

Corrected and extended by Sascha Kurz, Jan 28 2003

Status

approved