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 A364928 #14 Aug 26 2023 03:06:10 %S A364928 1,6,25,56,57,198,390,452,960,454,962,2105,3097,3128,4153,7185,10296, %T A364928 14353,15392,31744,65988,966,3129,6201,7193,7217,7224,10297,11320, %U A364928 14361,14392,15377,15400,15408,31752,31760,65990,66498,66500,98502,98756,99264 %N A364928 List of free corner-connected polyominoes in binary code (as defined in A246521), ordered first by number of bits, then by value of the binary code. %C A364928 Corner-connected polyominoes are in one-to-one correspondence with ordinary polyominoes, but their binary codes differ and the order in which they appear here is different from that in A246521. The first size for which the order differs from A246521 is 4 (tetrominoes). Here the order of the tetrominoes is (T, S, square, L, straight), whereas in A246521 it is (L, square, T, S, straight). %C A364928 Can be read as an irregular triangle, whose n-th row contains A000105(n) terms, n >= 1. %e A364928 As irregular triangle: %e A364928 1; %e A364928 6; %e A364928 25, 56; %e A364928 57, 198, 390, 452, 960; %e A364928 ... %e A364928 The corner-connected trominoes are oriented as follows to obtain their binary codes (see A246521): %e A364928 . . . 5 . . %e A364928 . 4 . . 4 . %e A364928 0 . 3 . . 3 %e A364928 This gives the binary codes 2^0+2^3+2^4 = 25 and 2^3+2^4+2^5 = 56, respectively. %e A364928 Similarly, for the corner-connected tetrominoes, the orientations %e A364928 . . . . . . . . . . . . . . . . 9 . . . %e A364928 5 . . . . . . . . 8 . . . 8 . . . 8 . . %e A364928 . 4 . . 2 . 7 . 2 . 7 . 2 . 7 . . . 7 . %e A364928 0 . 3 . . 1 . 6 . 1 . . . . . 6 . . . 6 %e A364928 give the binary codes 57, 198, 390, 452, 960, respectively. %Y A364928 Cf. A000105, A246521. %K A364928 nonn,tabf %O A364928 1,2 %A A364928 _Pontus von Brömssen_, Aug 13 2023