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 A023445 #24 Jul 08 2025 17:15:59 %S A023445 -3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22, %T A023445 23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45, %U A023445 46,47,48,49,50,51,52,53,54,55 %N A023445 n-3. %C A023445 For n >= 0, let M(n) be the matrix with first row = (n n+1) and 2nd row = (n+3 n+5). Then a(n) = det(M(n)). [From _K.V.Iyer_, Apr 11 2009] %H A023445 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A023445 Robert G. Wilson v, <a href="/A001477/a001477.txt">American English names for the numbers from 0 to 100999 without spaces or hyphens</a>. %H A023445 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A023445 a(n) = 2 a(n-1) - a(n-2). a(n) = -A022959(n). G.f.: (-3 + 4*x)/(1 - x)^2. - _M. F. Hasler_, Apr 18 2015 %t A023445 Range[0,60]-3 (* _Harvey P. Dale_, Dec 09 2017 *) %o A023445 (PARI) a(n)=n-3 %Y A023445 Cf. A256958, A001057, A000027, A001477, A023443, A023444, A023446, ..., A023482, A022958, ..., A022996. %K A023445 sign,easy %O A023445 0,1 %A A023445 _N. J. A. Sloane_