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A293974 Row sums of antidiagonals of the Sierpinski carpet A153490. 1
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 (list; graph; refs; listen; history; text; internal format)
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

Table of n, a(n) for n=1..72.

FORMULA

a(n) = A007953(A292688(n)) = A000120(A292689(n)) = sum(k=1..n, A153490(n,k)), considering A153490 as triangle; could also be indexed as matrix (m,n = 1,...,oo) or "flattened" (linearized) using A000217.

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!=2||j%3!=2))); sum(k=1, n, A[k, n-k+1])}

CROSSREFS

Cf. A153490, A292688, A292689, A000120, A007953, A000217.

Sequence in context: A292593 A214793 A199088 * A138557 A129303 A255368

Adjacent sequences:  A293971 A293972 A293973 * A293975 A293976 A293977

KEYWORD

nonn

AUTHOR

M. F. Hasler, Oct 24 2017

STATUS

approved

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Last modified September 18 18:23 EDT 2019. Contains 327178 sequences. (Running on oeis4.)