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A005733
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Least k such that binomial(k,n) has n or more distinct prime factors.
(Formerly M1166)
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3
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2, 4, 9, 10, 22, 26, 40, 50, 54, 55, 78, 115, 123, 154, 155, 209, 288, 220, 221, 292, 301, 378, 494, 494, 551, 715, 670, 786, 805, 803, 1079, 966, 1190, 1222, 1274, 1274, 1276, 1771, 1836, 1807, 1834, 2147, 2263, 2519, 2519, 3021, 3306, 3306, 3427, 3441, 3445
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Table 3 in Selmer's paper has typos for n = 83, 100 and 117. - T. D. Noe (noe(AT)sspectra.com), Apr 05 2007
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REFERENCES
| Selmer, Ernst S.; On the number of prime divisors of a binomial coefficient. Math. Scand. 39 (1976), no. 2, 271-281 (1977).
Selmer, Ernst S.; On the number of prime divisors of a binomial coefficient. Math. Scand. 39 (1976), no. 2, 271-281.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
Selmer, Ernst S.; On the number of prime divisors of a binomial coefficient. Math. Scand. 39 (1976), no. 2, 271-281.
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MATHEMATICA
| Table[n=k; b=1; While[n++; b=b*n/(n-k); Length[FactorInteger[b]]<k]; n, {k, 100}] - T. D. Noe (noe(AT)sspectra.com), Apr 05 2007
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CROSSREFS
| Cf. A005735, A129233.
Sequence in context: A103078 A060756 A075347 * A096692 A203847 A172147
Adjacent sequences: A005730 A005731 A005732 * A005734 A005735 A005736
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Edited by T. D. Noe (noe(AT)sspectra.com), Apr 05 2007
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