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 A306841 #17 Mar 26 2019 20:15:52 %S A306841 1,1,1,3,1,3,1,4,2,4,1,6,1,5,2,7,1,7,1,8,2,7,1,10,2,8,2,10,1,11,1,11, %T A306841 2,10,2,14,1,11,2,14,1,14,1,14,3,13,1,17,2,15,2,16,1,17,2,18,2,16,1, %U A306841 21,1,17,3,20,2,20,1,20,2,21,1,24,1,20,3,22,2,23 %N A306841 Number of rectangles of integer sides whose area or perimeter is n. %H A306841 MathOverflow, <a href="https://mathoverflow.net/q/324654">Tiling a square with rectangles whose areas or perimeters are 1, 2, 3, ..., N</a> %F A306841 a(n) = ceiling(d(n)/2) + floor(n/4) if n is even, a(n) = ceiling(d(n)/2) otherwise, where d(n) is the number of divisors of n. %e A306841 a(4) = 3 because there are two rectangles of integer sides of area 4 (2 X 2 and 1 X 4) and one rectangle of integer sides of perimeter 4 (1 X 1). %Y A306841 Cf. A038548 (area n), A004526 (perimeter 2n). %K A306841 nonn %O A306841 1,4 %A A306841 _Freddy Barrera_, Mar 12 2019