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 A053373 #29 Apr 14 2019 10:59:09 %S A053373 1,1,2,1,1,8,2,10,1,40,5,2,3,250,1,1,106,3,1138,2,8,25,146,2968,15, %T A053373 298,16,2,5,17,1856,1,1,9384,97,10,253970,2,72664,3,6440,5,521904,1,1, %U A053373 3034,5,9148450,1084152,117,2,746,10,88,157,126890,1,1,1311,56,287 %N A053373 Write fundamental unit for real quadratic field of discriminant n as x + y*omega; sequence gives values of y for n == 1 (mod 4). %C A053373 Entries are indexed by values of n from A039955. %C A053373 Subsequence of A077058 excluding terms for which A077425(n) is not squarefree. - _Max Alekseyev_, Dec 12 2012 %D A053373 R. A. Mollin, Quadratics, CRC Press, 1996, Tables B1-B3. %H A053373 Emmanuel Vantieghem, <a href="/A053373/b053373.txt">Table of n, a(n) for n=1..1000</a> %H A053373 S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/">Class number theory</a> %H A053373 Steven R. Finch, <a href="/A000924/a000924.pdf">Class number theory</a> [Cached copy, with permission of the author] %t A053373 2*NumberFieldFundamentalUnits[ Sqrt[#] ][[1, 2, 2]] & /@ Select[ Range[5, 309, 4], SquareFreeQ ] (* _Jean-François Alcover_, Jul 09 2013 *) %o A053373 (PARI) forstep(n=5,1000,4, if(!issquarefree(n),next); print1( 2*polcoeff(lift(bnfinit(x^2-n).fu[1]),1), ", " )) /* _Max Alekseyev_ */ %Y A053373 Cf. A053370-A053375. %K A053373 nonn,easy,nice %O A053373 1,3 %A A053373 _N. J. A. Sloane_, Jan 06 2000