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 A116903 #17 Aug 04 2020 06:52:47 %S A116903 1,3,7,19,49,131,339,899,2345,6199,16225,42811,112285,296051,777411, %T A116903 2049025,5384855,14190509,37313977,98324565,258654441,681552747, %U A116903 1793492411,4725856129,12439233695,32778031159,86295460555,227399388019,598784536563,1577923781445,4155176578581 %N A116903 Seaweeds(n): number of n-step self-avoiding walks on upper two quadrants grid starting at origin. %C A116903 These walks remind me of fluctuant seaweeds anchored to the sea bottom. %H A116903 M. N. Barber et al., <a href="https://doi.org/10.1088/0305-4470/11/9/017">Some tests of scaling theory for a self-avoiding walk attached to a surface</a>, 1978 J. Phys. A: Math. Gen. 11 1833. [_Vladeta Jovovic_, Nov 26 2008] %e A116903 The 19 seaweeds of length 3. X marks the origin = anchor point. %e A116903 ........................................................ %e A116903 O-O-O...O-O.. .O-O...O-O....O..O-O-O...O......O..O-O.... %e A116903 ....|.....|.. .|.....|......|..|.......|......|....|.... %e A116903 ....X...X-O....O.....O-X....O..X..O-O..O-O....O....O-X.. %e A116903 ...............|............|.......|....|....|......... %e A116903 O-O.....O-O....X....O.......O..O....O....X..X-O.......O. %e A116903 |.|.....|...........|.......|..|....|.................|. %e A116903 X.O...X-O.....O-O...O-O-X...X..O....X.....O.........O-O. %e A116903 ..............|.|..............|..........|.........|... %e A116903 ..X-O-O-O.....O.X...O-O-O-X....O-X....X-O-O.........X... %e A116903 ........................................................ %Y A116903 Cf. A001411, A038373, A116903. %K A116903 nonn %O A116903 0,2 %A A116903 _Giovanni Resta_, Feb 15 2006 %E A116903 a(23)-a(30) from _Scott R. Shannon_, Jul 26 2020