login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Triangle read by rows, square of Sierpinski's gasket, (A047999)^2
1

%I #9 Aug 08 2018 04:29:56

%S 1,2,1,2,0,1,4,2,2,1,2,0,0,0,1,4,2,0,0,2,1,4,0,2,0,2,0,1,8,4,4,2,4,2,

%T 2,1,2,0,0,0,0,0,0,0,1,4,2,0,0,0,0,0,0,2,1,4,0,2,0,0,0,0,0,2,0,1

%N Triangle read by rows, square of Sierpinski's gasket, (A047999)^2

%C Row sums = A048883: (1, 3, 3, 9, 3, 9, 9, 27, 3, 9, 9, 27,...)

%C Left border = A001316

%H E. Burlachenko, <a href="https://arxiv.org/abs/1612.00970">Fractal generalized Pascal matrices</a>, arXiv:1612.00970 [math.NT], 2016. See p. 13.

%F (A047999)^2, as an infinite lower triangular matrix.

%e First few rows of the triangle =

%e 1;

%e 2, 1;

%e 2, 0, 1;

%e 4, 2, 2, 1;

%e 2, 0, 0, 0, 1;

%e 4, 2, 0, 0, 2, 1;

%e 4, 0, 2, 0, 2, 0, 1;

%e 8, 4, 4, 2, 4, 2, 2, 1;

%e 2, 0, 0, 0, 0, 0, 0, 0, 1;

%e 4, 2, 0, 0, 0, 0, 0, 0, 2, 1;

%e 4, 0, 2, 0, 0, 0, 0, 0, 2, 0, 1;

%e 8, 4, 4, 2, 0, 0, 0, 0, 4, 2, 2, 1;

%e 4, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 1;

%e ...

%t rows = 11;

%t T = PadRight[#, rows]& /@ Mod[NestList[Prepend[#, 0] + Append[#, 0]&, {1}, rows-1], 2];

%t T2 = T.T;

%t Table[T2[[i, j]], {i, 1, rows}, {j, 1, i}] // Flatten (* _Jean-François Alcover_, Aug 08 2018, after _Robert G. Wilson v_ *)

%Y A047999, A001316

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Oct 13 2009