A093697 Least k so that n! >= primorial(k).

1, 1, 2, 3, 4, 5, 6, 7, 7, 8, 9, 10, 10, 11, 12, 13, 14, 14, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 23, 23, 24, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 33, 33, 34, 35, 36, 37, 37, 38, 39, 40, 40, 41, 42, 43, 43, 44, 45, 46, 47, 47, 48, 49, 50, 50, 51, 52, 53, 53, 54, 55, 56, 57

Offset

1,3

Links

Table of n, a(n) for n=1..73.

Example

a(9) = 7 because p#_6 = 30030 < 9! = 362880 < p#_7 = 510510.

Mathematica

Primorial[n_] := Product[ Prime[i], {i, n}]; f[n_] := Block[{k = 1}, While[ Primorial[k] < n!, k++ ]; k]; Table[ f[n], {n, 75}]

Crossrefs

Cf. A048964.

Sequence in context: A252649 A095703 A101041 * A157466 A194260 A227394

Adjacent sequences: A093694 A093695 A093696 * A093698 A093699 A093700

Keyword

easy,nonn

Author

Robert G. Wilson v, Apr 09 2004

Status

approved