A058422 Squares composed of digits {0,1,8}, not ending with zero.

1, 81, 11881, 811801, 1018081, 81018001, 100180081, 108180801, 8100180001, 10001800081, 10181011801, 810001800001, 1000018000081, 1008018008001, 80181118180881, 81000018000001, 100000180000081, 100180101018001, 1180000888001881, 8100000180000001, 10000001800000081

Offset: 1

Author

Patrick De Geest, Nov 15 2000

Keywords

• nonn
• base

Comments

Includes all numbers of the forms (10^k + 9)^2, (9*10^k + 1)^2, (100^k + 4*10^k + 1)^2, and (10*100^k + 9*10^k + 1)^2 for k >= 2. - Andrew Howroyd, Oct 18 2024

Links

• Zhao Hui Du, Table of n, a(n) for n = 1..91
• Patrick De Geest, Index to related sequences
• Hisanori Mishima, Sporadic tridigital solutions

Crossrefs

Cf. A058421.

Programs

Mathematica

Select[FromDigits/@Tuples[{0,1,8},17],Mod[#,10]!=0&&IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Sep 09 2022 *)

Formula

a(n) = A058421(n)^2. - Andrew Howroyd, Oct 18 2024