A072120 Least k such that n! divides C(2k,k).

1, 1, 2, 7, 14, 15, 43, 191, 239, 383, 383, 1919, 1919, 3967, 4091, 65471, 65471, 129023, 129023, 516095, 516095, 917503, 1046527, 8323071, 8323071, 16760831, 16760831, 113246207, 113246207, 367001599, 367001599, 4294967291

Offset

1,3

Links

Table of n, a(n) for n=1..32.

Mathematica

a[n_] := Block[{k = 1}, While[ !IntegerQ[ Binomial[2k, k] / n! ], k++ ]; k]; Table[ a[n], {n, 1, 16}]

Prog

(PARI) for(n=1, 16, s=1; while(binomial(2*s, s)%n!>0, s++); print1(s, ", "))

Crossrefs

Sequence in context: A368895 A331703 A032537 * A247866 A057126 A363026

Adjacent sequences: A072117 A072118 A072119 * A072121 A072122 A072123

Keyword

nonn

Author

Benoit Cloitre, Jun 19 2002

Extensions

Edited and extended by Robert G. Wilson v, Jun 21 2002

More terms from Naohiro Nomoto, Jun 26 2002

More terms from Don Reble, Jul 01 2002

Status

approved