A053887 Squares composed of digits {1,2,8}.
1, 81, 121, 8281, 11881, 128881, 11282881, 228281881, 1112822881, 111128222881, 11111282222881, 222128888112121, 228828882122281, 812121128112121, 1111112822222881, 8181222218111881, 111111128222222881, 11111111282222222881, 1111111112822222222881, 2118128181211211281281
Offset: 1
Links
- Zhao Hui Du, Table of n, a(n) for n = 1..44
- Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences.
Crossrefs
Cf. A053886.
Programs
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Mathematica
Table[Select[FromDigits/@Tuples[{1,2,8},n],IntegerQ[Sqrt[#]]&],{n,18}]//Flatten (* Harvey P. Dale, Jun 03 2022 *)
Formula
a(n) = A053886(n)^2. - Andrew Howroyd, Oct 18 2024
Comments