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 A261363 #12 May 13 2025 02:39:56 %S A261363 1,1,2,1,1,2,1,2,3,4,1,1,1,1,2,1,2,2,2,3,4,1,1,2,2,3,3,4,1,2,3,4,5,6, %T A261363 7,8,1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,3,4,1,1,2,2,2,2,2,2,3,3,4,1,2, %U A261363 3,4,4,4,4,4,5,6,7,8,1,1,1,1,2,2,2,2,3,3,3,3,4 %N A261363 Triangle read by rows: partial row sums of Sierpinski's triangle. %C A261363 T(n,n) = number of distinct terms in row n = number of odd terms in row n+1 = A001316(n). %C A261363 Central terms, for n > 0: T(2*n,n) = A048896(n-1). %H A261363 Reinhard Zumkeller, <a href="/A261363/b261363.txt">Rows n = 0..125 of triangle, flattened</a> %e A261363 . n | Sierpinski: A047999(n,*) | Partial row sums: T(n,*) %e A261363 . ----+----------------------------+---------------------------- %e A261363 . 0 | 1 | 1 %e A261363 . 1 | 1 1 | 1 2 %e A261363 . 2 | 1 0 1 | 1 1 2 %e A261363 . 3 | 1 1 1 1 | 1 2 3 4 %e A261363 . 4 | 1 0 0 0 1 | 1 1 1 1 2 %e A261363 . 5 | 1 1 0 0 1 1 | 1 2 2 2 3 4 %e A261363 . 6 | 1 0 1 0 1 0 1 | 1 1 2 2 3 3 4 %e A261363 . 7 | 1 1 1 1 1 1 1 1 | 1 2 3 4 5 6 7 8 %e A261363 . 8 | 1 0 0 0 0 0 0 0 1 | 1 1 1 1 1 1 1 1 2 %e A261363 . 9 | 1 1 0 0 0 0 0 0 1 1 | 1 2 2 2 2 2 2 2 3 4 %e A261363 . 10 | 1 0 1 0 0 0 0 0 1 0 1 | 1 1 2 2 2 2 2 2 3 3 4 %e A261363 . 11 | 1 1 1 1 0 0 0 0 1 1 1 1 | 1 2 3 4 4 4 4 4 5 6 7 8 %e A261363 . 12 | 1 0 0 0 1 0 0 0 1 0 0 0 1 | 1 1 1 1 2 2 2 2 3 3 3 3 4 . %t A261363 row[n_] := Accumulate[Array[Boole[0 == BitAnd[n-#, #]] &, n + 1, 0]]; Array[row, 13, 0] // Flatten (* _Amiram Eldar_, May 13 2025 *) %o A261363 (Haskell) %o A261363 a261363 n k = a261363_tabl !! n !! k %o A261363 a261363_row n = a261363_tabl !! n %o A261363 a261363_tabl = map (scanl1 (+)) a047999_tabl %Y A261363 Cf. A047999, A008949, A048896 (central terms), A001316 (right edge), A261366. %K A261363 nonn,tabl,easy %O A261363 0,3 %A A261363 _Reinhard Zumkeller_, Aug 16 2015