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A077676
Squares using only squarefree digits (2, 3, 5, 6, 7).
3
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
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
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 16 2002
EXTENSIONS
Corrected and extended by Sascha Kurz, Jan 28 2003
STATUS
approved