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 A383345 #24 Aug 19 2025 23:05:39 %S A383345 1,4,14,52,210,816,3206,12536,48962,191226,746456,2913544,11371040, %T A383345 44376798,173181564,675834086,2637392942,10292179494,40164144690, %U A383345 156736057740,611644171812,2386868430698,9314465669046 %N A383345 Number of uniquely solveable n X 2 nonograms (hanjie). %C A383345 In this game there is an n X 2 grid where each square may or may not be filled. Each column and each row is labeled by the length of each successive block of filled squares, but without indication of the number of unfilled squares in between. The object is to determine which squares are filled. %C A383345 The only ambiguous row hint is 1, which has the same solutions regardless of whether black or white squares are counted. So this is also the number of n X 2 "yesnograms". %H A383345 Bertram Felgenhauer, <a href="https://int-e.eu/nono/">Counting Nonograms</a>. %H A383345 Wikipedia, <a href="https://en.wikipedia.org/wiki/Nonogram">Nonogram</a>. %e A383345 a(2) = 16-2 because out of the possible 2^(2*2) grids, only 10/01 and 01/10 have the same row and column clues. %Y A383345 Column m=2 of A384764. Also column m=2 of A385862 (n X m yesnograms). %Y A383345 Cf. A242876. %K A383345 nonn,hard %O A383345 0,2 %A A383345 _Bertram Felgenhauer_, Jun 11 2025