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A143544
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Triangle read by rows, T(n,k) = 2 if n is prime, 1 otherwise; 1<=k<=n.
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2
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1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
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OFFSET
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1,2
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COMMENTS
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Row sums = A143545: (1, 4, 6, 4, 10, 6, 14,...) = componentwise addition of (1, 2, 3, 4, 5,...) and A061397: (0, 2, 3, 0, 5, 0, 7,...).
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LINKS
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FORMULA
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Triangle read by rows, T(n,k) = 2 if n is prime, 1 otherwise; 1<=k<=n.
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EXAMPLE
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First few rows of the triangle =
1;
2, 2;
2, 2, 2;
1, 1, 1, 1;
2, 2, 2, 2, 2;
1, 1, 1, 1, 1, 1;
2, 2, 2, 2, 2, 2, 2;
...
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MATHEMATICA
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Table[1 + Boole[PrimeQ[n]], {n, 11}, {k, n}] // Flatten (* Michael De Vlieger, Oct 31 2021 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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