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A129508
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Numbers n such that 3 and 5 do not divide binomial(2n,n).
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6
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0, 1, 10, 12, 27, 30, 31, 36, 37, 252, 255, 256, 280, 282, 756, 757, 760, 810, 811, 3160, 3162, 3186, 3187, 3250, 3252, 3276, 3277, 3280, 6561, 6562, 6885, 6886, 6912, 6925, 7536, 7537, 7560, 7561, 7626, 7627, 7650, 7651, 19686, 19687, 20007, 20010, 20011
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OFFSET
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1,3
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COMMENTS
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The Erdos paper proves that for any two odd primes p and q, there are an infinite number of n for which gcd(p*q,binomial(2n,n))=1; i.e., p and q do not divide binomial(2n,n).
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LINKS
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FORMULA
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MATHEMATICA
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lim=10000; Intersection[Table[FromDigits[IntegerDigits[k, 2], 3], {k, 0, lim}], Table[FromDigits[IntegerDigits[k, 3], 5], {k, 0, lim}]]
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PROG
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(PARI) valp(n, p)=my(s); while(n\=p, s+=n); s
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CROSSREFS
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Cf. A030979 (n such that 3, 5 and 7 do not divide binomial(2n, n)).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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