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 A061525 #9 Aug 13 2020 14:01:06 %S A061525 83,361,951,1997,3667,6153,9671,14461,20787,28937,39223,51981,67571, %T A061525 86377,108807,135293,166291,202281,243767,291277,345363,406601,475591, %U A061525 552957,639347,735433,841911,959501,1088947,1231017,1386503,1556221 %N A061525 Surround numbers of an n X 2 rectangle when n is odd. %C A061525 See A061524 for even n. %H A061525 E. J. Friedman, <a href="https://erich-friedman.github.io/mathmagic/0599.html">Math. Magic: May, 1999</a> %F A061525 a(n) = (n^4 + 32n^3 + 278n^2 + 656n + 361)/16 when n is odd. %F A061525 From _Chai Wah Wu_, Dec 20 2019: (Start) %F A061525 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 5. %F A061525 G.f.: x*(3*x^4 - 22*x^3 + 24*x^2 + 54*x - 83)/(x - 1)^5. (End) %Y A061525 Cf. A047875 A061524. %K A061525 easy,nonn %O A061525 1,1 %A A061525 _Jason Earls_, May 03 2001 %E A061525 More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001