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A048571
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Triangle read by rows: T(n,k) = number of distinct prime factors of C(n,k).
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4
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0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 2, 2, 2, 2, 2, 0, 0, 1, 2, 2, 2, 2, 1, 0, 0, 1, 2, 2, 3, 2, 2, 1, 0, 0, 1, 2, 3, 3, 3, 3, 2, 1, 0, 0, 2, 2, 3, 4, 3, 4, 3, 2, 2, 0, 0, 1, 2, 3, 4, 4, 4, 4, 3, 2, 1, 0, 0, 2, 3, 3, 3, 3, 4, 3, 3, 3, 3, 2, 0
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,13
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REFERENCES
| Pierre Goetgheluck, On prime divisors of binomial coefficients, Math. Comp. 51 (1988), no. 183, 325-329.
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LINKS
| T. D. Noe, Rows n=0..100 of triangle, flattened
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EXAMPLE
| Triangle begins:
0
0,0
0,1,0
0,1,1,0
0,1,2,1,0
0,1,2,2,1,0
0,2,2,2,2,2,0
0,1,2,2,2,2,1,0
...
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MATHEMATICA
| Flatten[Table[b=Binomial[n, k]; Length[FactorInteger[b]], {n, 0, 12}, {k, 0, n}]] - T. D. Noe (noe(AT)sspectra.com), Oct 19 2007
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CROSSREFS
| Cf. A132896.
Sequence in context: A137867 A111143 A004197 * A025880 A058755 A128519
Adjacent sequences: A048568 A048569 A048570 * A048572 A048573 A048574
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KEYWORD
| nonn,tabl
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com); edited Oct 06 2007 at the suggestion of T. D. Noe.
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EXTENSIONS
| Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 19 2007
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