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 A255744 #26 Nov 03 2022 08:43:13 %S A255744 1,10,10,90,10,90,90,810,10,90,90,810,90,810,810,7290,10,90,90,810,90, %T A255744 810,810,7290,90,810,810,7290,810,7290,7290,65610,10,90,90,810,90,810, %U A255744 810,7290,90,810,810,7290,810,7290,7290,65610,90,810,810,7290,810,7290 %N A255744 a(1) = 1; for n > 1, a(n) = 10*9^(A000120(n-1)-1). %C A255744 Also, this is a row of the square array A255740. %C A255744 Partial sums give A255765. %H A255744 Felix Fröhlich, <a href="/A255744/b255744.txt">Table of n, a(n) for n = 1..10000</a> %e A255744 Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins: %e A255744 1; %e A255744 10; %e A255744 10, 90; %e A255744 10, 90, 90, 810; %e A255744 10, 90, 90, 810, 90, 810, 810, 7290; %e A255744 ... %t A255744 MapAt[Floor, Array[10*9^(DigitCount[# - 1, 2, 1] - 1) &, 54], 1] (* _Michael De Vlieger_, Nov 03 2022 *) %o A255744 (PARI) a(n) = if (n==1, 1, 10*9^(hammingweight(n-1)-1)); \\ _Michel Marcus_, Mar 15 2015 %Y A255744 Cf. A000120, A151787, A147582, A151789, A151779, A151791, A151782, A255740, A255741, A255743, A255745, A255765. %K A255744 nonn %O A255744 1,2 %A A255744 _Omar E. Pol_, Mar 05 2015 %E A255744 More terms from _Michel Marcus_, Mar 15 2015