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 A273089 #25 Mar 27 2020 06:37:31 %S A273089 0,0,0,0,0,0,0,3,0,0,5,6,0,0,584,882,0,0,18026,194741,0,0,644414, %T A273089 960834,0,0,229910636 %N A273089 Number of lattice n-gons with ordered sides 1, 2, 3, ..., n. %C A273089 First 16 terms calculated by Stefan Kohl. %H A273089 Stefan Kohl, <a href="https://mathoverflow.net/a/237741">Lattice n-gons with ordered side lengths 1,2,3,…,n</a>, Answer on MathOverflow, May 4, 2016. %H A273089 MathOverflow, <a href="http://mathoverflow.net/questions/237374/lattice-n-gons-with-ordered-side-lengths-1-2-3-n">Lattice n-gons with ordered side lengths 1,2,3,...,n</a> %H A273089 Giovanni Resta, <a href="/A273089/a273089.pdf">Examples of n-gons with minimal and maximal area</a> %H A273089 L. Sallows, M. Gardner, R. K. Guy and D. E. Knuth, <a href="http://www.jstor.org/stable/2690648">Serial isogons of 90 degrees</a>, Math. Mag. 64 (1991), 315-324. %H A273089 Wikipedia, <a href="https://en.wikipedia.org/wiki/Golygon">Golygon</a> %e A273089 a(8) = 3: %e A273089 . . . . . ._._._. . . . . . . . . ._._._._._._._. %e A273089 . . . . . | . . | . . . . . . . . | . . . . . . | %e A273089 . . . . . | . ._| ._._._._._._._. | . . . . . . | %e A273089 . . . . . | . | . | . . . . . . | | . . . . . . | %e A273089 ._._._._._| . | . | . . . . . | | . . . . . . | %e A273089 | . . . . . . | . | . . . |\. . | | . . . . . . | %e A273089 | . . . . . . | . | . . . | \ . | | ._._._. . . | %e A273089 | . . . . . . | . | . . . | .\5 | | | . . | . ./. %e A273089 | . . . . . . | . | ._._._| . .\| |_| . . | ./5 . %e A273089 | . . . . . . | . | | . . . . . . . . . . | / . . %e A273089 |_._._._._._._| . |_| . . . . . . . . . . |/. . . %e A273089 . %e A273089 a(11) = 5: %e A273089 . . . . . . . . . . . ._._._._._._._._._. . . . . . . . %e A273089 . . . . . . . . . . . .\. . . . . . . . | . . . . . . . %e A273089 . . . . . . . . . . . . . \ . . . . . . | . . . . . . . %e A273089 . . . . . . . ._._._. . . . .\. . . . . | . . . . . . . %e A273089 . . . . . . . | . . | . . . . .10 . . . | . . . . . . . %e A273089 . . . . . . ._| . . | . . . . . . \ . . | . . . . . . . %e A273089 . . . . . . | . . . | . . . . . . . .\. | . . . . . . . %e A273089 . . . . . . | . . . | . . . . . . . . | | . . . . . . . %e A273089 . . . . . . | . . . . \ . . . . . . . | |_._._._._._._. %e A273089 |\. . . . . | . . . . . 5 \ . . . . . | . . . . . . . | %e A273089 | \ . . . . | . ._._._._._._. . . . . | . . . . . . . | %e A273089 | .\. . . . | . | . . . . . . . . . . | . . . . . . . | %e A273089 | . .\. . . | . | . . . . . . . . . . | . . . | \ . . | %e A273089 | . . 10. . | . | . . . . . . . . . . | . . . | . 5 . | %e A273089 | . . . \ . | . | . . . . . . . . . . | . . . | . . \ | %e A273089 | . . . . \ | . | . . . . . . . . . . | ._._._| . . . . %e A273089 | . . . . .\| . | . . . . . . . . . . | | . . . . . . . %e A273089 |_._._._._._._._| . . . . . . . . . . |_| . . . . . . . %e A273089 . %e A273089 . ._._._. . . . . . . . . . . . . . . . . . . . . . . . . . . . %e A273089 . | . . | . . . . . . . . . . . . . . . . . ./| . . . . . . . . %e A273089 ._| . . | . . . . . . . . . . . . . . . . ./. | . . . . . . . . %e A273089 | . . . | . . . . . . . . . . . . . . . . / . | . . . . . . . . %e A273089 | . . . | . . . . . . . . . . . . . . . ./. . | . . . . . . . . %e A273089 | . . . .\. . . . . . . . . . . . . . .10 . . | . . . . . . . . %e A273089 | . . . . . 5 . . . . . . . . . . . . / . . . | . . . . . . . . %e A273089 | . . . . . . .\. . . . . . . . . . / . . . . | . . . . . . . . %e A273089 | . . . . . . . | . . . . . . . . ./. . . . . | . . . . . . . . %e A273089 | . . . . . . . | . . . . . . . . | . . . . . |_._._._._._._._. %e A273089 | . . . . . . . | . . . . . . . . | . . . . . . . . . . . . . | %e A273089 | . . . . . . . | . . . . . . . . | . . . . . . . . . . . . . | %e A273089 | . . . . . . . | . . . . . . . . | . . . . . . . . . . . . . | %e A273089 | . . . . . . . |_._._._._._._. . | . . . . . . . . . . . . . | %e A273089 .\. . . . . . . . . . . . . . | . | . . . | \ . . . . . . . . | %e A273089 . \ . . . . . . . . . . . . . | . | . . . | . .5. . . . . . . | %e A273089 . . \ . . . . . . . . . . . . | . | . . . | . . .\._._._._._._| %e A273089 . . . \ . . . . . . . . . . . | . | ._._._| . . . . . . . . . . %e A273089 . . . 10. . . . . . . . . . . | . | | . . . . . . . . . . . . . %e A273089 . . . . \ . . . . . . . . . . | . |_| . . . . . . . . . . . . . %e A273089 . . . . . \ . . . . . . . . . | %e A273089 . . . . . .\._._._._._._._._._| %e A273089 . %e A273089 . . . . . . . . . . . . . . . . %e A273089 |\. . . . . . . . . . . . . . . %e A273089 | .\. . . . . . . . . . . . . . %e A273089 | . \ . . . . . . . . . . . . . %e A273089 | . . \ . . . . . . . . . . . . %e A273089 | . . 10. . . . . . . . . . . . %e A273089 | . . . .\. . . . . . . . . . . %e A273089 | . . . . \ . . . . . . . . . . %e A273089 | . . . . . \_._._._._._._._._. %e A273089 | ._._._. . . . . . . . . . . | %e A273089 | | . . | . . . . . . . . . . | %e A273089 |_| . . | . . ./| . . . . . . | %e A273089 . . . . | . 5 . | . . . . . . | %e A273089 . . . . |/. . . | . . . . . . | %e A273089 . . . . . . . . | . . . . . . | %e A273089 . . . . . . . . | . . . . . . | %e A273089 . . . . . . . . |_._._._._._._| %e A273089 . - _Hugo Pfoertner_, Mar 20 2020 %Y A273089 Cf. A007219. %K A273089 nonn,hard,more %O A273089 1,8 %A A273089 _Bernardo Recamán_, May 14 2016 %E A273089 Typo in a(15) corrected and a(17)-a(27) added by _Giovanni Resta_, Mar 26 2020