A053898 Numbers k such that k^2 contains only digits {1,4,7}.

1, 2, 12, 21, 38, 88, 2729, 2036462, 2678521, 1203108962, 343143082067979, 2678520388463521, 1071033028175028538, 2177492084289725902412

Offset: 1

Author

Patrick De Geest, Mar 15 2000

Keywords

• nonn
• base
• more

Links

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

Crossrefs

Cf. A053899.

Programs

Mathematica

Select[Range[1, 10000],ContainsOnly[IntegerDigits[#^2], {1, 4, 7}] &] (* Julien Kluge, Jul 08 2016 *)

Extensions

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 04 2005

Four more terms from Mishima's webpage added by Max Alekseyev, Jan 28 2012