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A090971 Sierpiński's triangle, read by rows, starting from 1: T(n,k) = (T(n-1,k) + T(n-1,k-1)) mod 2. 2
1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums give A038573.

LINKS

G. C. Greubel, Rows n = 1..100 of triangle, flattened

FORMULA

From Philippe Deléham, Feb 29 2004: (Start)

Triangle A047999(n, k) for n > 0 and k > 0; A047999: Pascal's triangle mod 2.

a(n) = A062534(n-1) mod 2.

T(n-1, k-1) = A074909(n, n-k) mod 2.

EXAMPLE

Triangle begins with:

  1;

  0, 1;

  1, 1, 1;

  0, 0, 0, 1;

  1, 0, 0, 1, 1;

  0, 1, 0, 1, 0, 1;

  1, 1, 1, 1, 1, 1, 1; ...

MATHEMATICA

T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[k==n, 1, Mod[T[n-1, k] + T[n-1, k-1], 2]]]; Table[T[n, k], {n, 1, 10}, {k, 1, n}] (* G. C. Greubel, Feb 03 2019 *)

PROG

(PARI) T(n, k)=if(k<0 || k>n, 0, if(n==0, 1, (T(n-1, k)+T(n-1, k-1))%2))

CROSSREFS

Cf. A007318.

Sequence in context: A267814 A267272 A181656 * A105594 A091949 A039984

Adjacent sequences:  A090968 A090969 A090970 * A090972 A090973 A090974

KEYWORD

nonn,tabl

AUTHOR

Benoit Cloitre, Feb 28 2004

STATUS

approved

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Last modified April 22 22:19 EDT 2021. Contains 343197 sequences. (Running on oeis4.)