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 A186297 #13 Jun 10 2023 13:24:36 %S A186297 1,5,9,21,29,33,41,53,65,69,81,89,105,113,125,141,153,165,173,189,209, %T A186297 221,233,245,249,261,273,281,285,293,309,321,329,341,345,369,393,405, %U A186297 413,429,441,453,473,485,509,525,545,561,581,585,593 %N A186297 a(n) = (A007520(n)-1)/2. %C A186297 a(n) = A055034(A007520(n)), n >= 1. This is the degree of the minimal polynomial C(A007520(n) ,x) of 2*cos(Pi/A007520(n)) (see A187360). a(n) is of course congruent 1 (mod 4). - _Wolfdieter Lang_, Oct 24 2013 %F A186297 a(n) = A186296(n)-1. %Y A186297 Cf. A007520, A055034, A186296, A187360. %K A186297 nonn %O A186297 1,2 %A A186297 _Marco Matosic_, Feb 17 2011