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A087760
Numbers n such that the sequence of k>=2 such that k^3 divides {binomial(n*k,k)-n} coincides exactly with the sequence of prime numbers.
0
4, 12, 13, 16, 21, 24, 37, 40, 48, 52, 57, 60, 61, 69, 73, 76, 84, 85, 88, 93, 105, 109, 112, 120, 124, 132, 133, 141, 145, 148, 156, 157, 165, 168, 172, 177, 181, 184, 201, 204, 205, 208, 213, 217, 220, 228, 229, 232, 237, 240, 241, 249, 253, 264, 265, 268
OFFSET
1,1
COMMENTS
Needs to be checked. If p is prime >=m then p^3 divides {binomial(m*p,p)-m}.
EXAMPLE
The sequence of k>=2 such that k^3 divides {binomial(12*k,k)-12} is : 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53... which is exactly the sequence of prime numbers. Hence 12 is in the sequence.
PROG
(PARI) isok(n) = {my(nb = 0); for (k=2, n+10, if (!((binomial(n*k, k) - n) % k^3), nb++; if (k != prime(nb), return (0); )); ); return (1); } \\ Michel Marcus, Dec 06 2013; corrected Jun 13 2006
CROSSREFS
Sequence in context: A074138 A120252 A103053 * A237279 A032498 A377048
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Oct 02 2003
EXTENSIONS
More terms from Michel Marcus, Dec 06 2013
STATUS
approved