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.
%I A080161 #26 Feb 16 2025 08:32:48 %S A080161 1,2,3,4,5,6,7,8,9,36,51,66,81,102,123,144,225,258,291,324,363,402, %T A080161 441,576,593,610,627,644,661,678,695,712,729,748,767,786,805,824,843, %U A080161 862,881,900,1089,1158,1227,1296,1371,1446,1521,1764,1851,1938,2025 %N A080161 Indices of Wonderful Demlo numbers A002477 whose digit sums are squares. %C A080161 The numbers 9*n^2 (A016766), with n > 0, are in this sequence. - _Enrique Pérez Herrero_, Sep 26 2020 %H A080161 Jeppe Stig Nielsen, <a href="/A080161/b080161.txt">Table of n, a(n) for n = 1..10000</a> %H A080161 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DemloNumber.html">Demlo Number</a> %t A080161 A080151[n_] := (9^2)*(n/9 - FractionalPart[n/9] + FractionalPart[n/9]^2) %t A080161 Select[Range[10000], IntegerQ[Sqrt[A080151[#]]] &] %t A080161 (* _Enrique Pérez Herrero_, Sep 26 2020 *) %o A080161 (PARI) for(k=1,10^5,issquare((k\9)*81+(k%9)^2)&&print1(k,", ")) \\ _Jeppe Stig Nielsen_, May 27 2023 %Y A080161 Cf. A080160, A080162, A002477, A080151, A108690. %K A080161 nonn,base %O A080161 1,2 %A A080161 _Eric W. Weisstein_, Jan 31 2003