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 A380025 #34 Feb 01 2025 23:12:57 %S A380025 2,6,12,15,24,35,40,54,65,77,96,112,126,150,160 %N A380025 Area of smallest rectangle of grid cells such that it is possible to mark a connected subset of the cells so that the lengths of runs of marked cells have lengths from 2 to n, each length appearing exactly once. %C A380025 Runs may be horizontal or vertical and only lengths > 1 are considered. %C A380025 In the puzzle, the best solutions are the ones with the most free space (fewest marked cells). In this sequence, only the area of the smallest rectangle is considered. %C A380025 Terms a(6)-a(10) from _George Sicherman_. %C A380025 a(11) from Giorgio Vecchi. %H A380025 Rodolfo Kurchan, <a href="https://www.puzzlefun.online/problems">Crossword Polyominoes</a>, Puzzle Fun, Problems (2025). %e A380025 a(11) = 77 from the following 7 x 11 rectangle: %e A380025 2 to 11 = 77 (7 x 11) (30 free space). %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | X | X | X | X | X | X | X | X | X | X | X | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | | | | | | X | X | X | X | | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | X | X | X | X | X | X | X | X | X | X | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | | | | | | X | X | | X | | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | X | X | X | X | X | X | X | X | X | | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | | | | | | X | | | X | | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %e A380025 | X | X | X | X | X | X | X | X | | | | %e A380025 +---+---+---+---+---+---+---+---+---+---+---+ %Y A380025 Cf. A351516. %K A380025 nonn,more %O A380025 2,1 %A A380025 _Rodolfo Kurchan_, Jan 09 2025 %E A380025 a(12)-a(16) from _Rodolfo Kurchan_, Feb 01 2025