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 A054215 Squares that are concatenations of two consecutive decreasing numbers. 9
 8281, 82428241, 98029801, 538277538276, 998002998001, 7783702677837025, 9998000299980001, 79225472657922547264, 86432513458643251344, 92237976109223797609, 99998000029999800001, 106710893290106710893289 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Infinitely many terms of this sequence are provided by A168624(k)^2 for k>0. - Bruno Berselli, Mar 13 2018 REFERENCES Luca, Florian, and Pantelimon Stănică. "Perfect Squares as Concatenation of Consecutive Integers." The American Mathematical Monthly 126.8 (2019): 728-734. LINKS FORMULA a(n) = concatenation of A054214(n) and A054214(n)-1. - Max Alekseyev, May 14 2007 EXAMPLE E.g. '8242' + '8242-1' gives 82428241 which is 9079^2. CROSSREFS Cf. A054214, A054216, A030465, A030466, A030467, A020339, A020340. Sequence in context: A064014 A203881 A145527 * A031589 A031769 A280872 Adjacent sequences:  A054212 A054213 A054214 * A054216 A054217 A054218 KEYWORD nonn,base AUTHOR Patrick De Geest, Feb 15 2000 EXTENSIONS More terms from Max Alekseyev, May 14 2007 82848241 corrected to 82428241 by Dominick Cancilla, Jul 21 2010 STATUS approved

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Last modified July 24 14:27 EDT 2021. Contains 346273 sequences. (Running on oeis4.)