A053973 Squares composed of digits {6,7,9}.

9, 676, 69696, 97969, 9696996, 9697699776769, 77797697969777769, 776797677679677696, 6776696769676669969, 9767769967769766976, 97667999767779769677969, 7676999976999997667777796, 69997676676669667699797969, 67976976676979976697777676769, 96667776776767999797799699976676

Offset: 1

Author

Patrick De Geest, Mar 15 2000

Keywords

• nonn
• base

Links

• P. De Geest, Squares containing at most three distinct digits, Index entries for related sequences
• Author?, Source (txt)
• Hisanori Mishima, Sporadic tridigital solutions

Crossrefs

Cf. A053972.

Programs

Mathematica

Flatten[Table[Select[FromDigits/@Tuples[{6,7,9},i],IntegerQ[Sqrt[#]]&],{i,23}]] (* Harvey P. Dale, Dec 07 2014 *)

Formula

a(n) = A053972(n)^2.

Extensions

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 14 2005

a(12)-a(15) from Mishima's website, added by Max Alekseyev, Nov 30 2017