cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A028821 Numbers k such that k^2 has digits in nonincreasing order.

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%I A028821 #15 Feb 10 2025 21:32:15
%S A028821 0,1,2,3,8,9,10,20,21,29,30,31,80,88,90,100,200,210,290,300,310,800,
%T A028821 880,900,1000,2000,2100,2900,2979,3000,3100,3139,8000,8800,9000,10000,
%U A028821 20000,21000,29000,29790,30000,31000,31390,31621,80000,88000
%N A028821 Numbers k such that k^2 has digits in nonincreasing order.
%H A028821 Ray Chandler, <a href="/A028821/b028821.txt">Table of n, a(n) for n = 1..108</a>
%H A028821 Patrick De Geest, <a href="https://www.worldofnumbers.com/nobase10pg2.htm">Palindromic Squares in bases 2 to 17</a>
%t A028821 Select[Range[0,10^5],GreaterEqual@@IntegerDigits[#^2]&] (* _Ray Chandler_, Jan 05 2014 *)
%Y A028821 Cf. A028822.
%K A028821 nonn,base
%O A028821 1,3
%A A028821 _Patrick De Geest_
%E A028821 Better name from _Ray Chandler_, Jan 05 2014