

A293974


Row sums of antidiagonals of the Sierpinski carpet A153490.


3



1, 2, 2, 4, 5, 4, 6, 6, 4, 8, 10, 8, 13, 14, 10, 14, 13, 8, 14, 16, 12, 18, 18, 12, 16, 14, 8, 16, 20, 16, 26, 28, 20, 28, 26, 16, 29, 34, 26, 40, 41, 28, 38, 34, 20, 34, 38, 28, 41, 40, 26, 34, 29, 16, 30, 36, 28, 44, 46, 32, 44, 40, 24, 42, 48, 36, 54, 54, 36, 48, 42, 24
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OFFSET

1,2


COMMENTS

Also, sums of digits of terms of A292688, or Hamming weights of terms of A292689. See there or A153490 for definition / construction of the Sierpiski carpet.


LINKS



FORMULA



MATHEMATICA

A293974[i_]:=With[{a=Nest[ArrayFlatten[{{#, #, #}, {#, 0, #}, {#, #, #}}]&, {{1}}, i]}, Array[Total[Diagonal[a, #]]&, 3^i, 13^i]]; A293974[5] (* Generates 3^5 terms *) (* Paolo Xausa, May 14 2023 *)


PROG

(PARI) A293974(n, A=Mat(1))={while(#A<n, A=matrix(3*#A, 3*#A, i, j, if(A[(i+2)\3, (j+2)\3], i%3!=2j%3!=2))); sum(k=1, n, A[k, nk+1])}


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



