A053889 Squares composed of digits {1,2,9}.

1, 9, 121, 29929, 9991921, 1212919929, 1929229929, 1991212129, 2929299129, 1229129212921, 92222199291121, 219992999929921, 99221129991291219129, 2291192212129911919221121, 9992221299191112291912929211222129, 211192199129121999192121999211919121, 21112999921929291129929211912291229929191119991929921

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Author?, Source(txt)

P. De Geest, Squares containing at most three distinct digits, Index entries for related sequences

H. Mishima, Squares consisting of 3 different digits

Mathematica

Flatten[Table[Select[FromDigits/@Tuples[{1, 2, 9}, n], IntegerQ[Sqrt[#]]&], {n, 12}]] (* This program generates only the first 9 terms of the sequence *) (* Harvey P. Dale, Oct 19 2011 *)

Crossrefs

Cf. A053888.

Sequence in context: A045976 A276256 A276095 * A295372 A293284 A087584

Adjacent sequences: A053886 A053887 A053888 * A053890 A053891 A053892

Keyword

nonn,base

Author

Patrick De Geest, Mar 15 2000

Extensions

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

One more term from Jon E. Schoenfield, Sep 03 2006

Two more terms from Mishima's webpage added by Max Alekseyev, Jun 17 2011

a(17) from Zhao Hui Du, Feb 29 2024

Status

approved