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 A031618 #14 Aug 18 2021 00:10:32 %S A031618 5801,11498,18577,28345,29021,39373,40169,51754,54049,66853,85625, %T A031618 100297,102841,121633,124433,125138,126554,142001,143509,144266, %U A031618 145786,146549,148081,150394,170473,175453,194441,201545,218117,219985,224690 %N A031618 Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 30. %Y A031618 Subsequence of A003814. %K A031618 nonn %O A031618 1,1 %A A031618 _David W. Wilson_ %E A031618 First term 901 removed by _Georg Fischer_, Jun 16 2019