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A048964 a(n) is smallest number k such that k! >= n-th primorial number (A002110(n)). 4
2, 3, 5, 6, 7, 8, 10, 11, 12, 14, 15, 16, 17, 19, 20, 21, 23, 24, 25, 27, 28, 29, 31, 32, 33, 34, 36, 37, 38, 40, 41, 42, 44, 45, 46, 47, 49, 50, 51, 53, 54, 55, 57, 58, 59, 60, 62, 63, 64, 66, 67, 68, 70, 71, 72, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 86, 88, 89, 90, 92, 93 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If in the definition '>=' is replaced by '>' we get A073071. - Bernard Schott, Feb 20 2021

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000

EXAMPLE

9! = 362880 < A002110(7) = 2*3*5*7*11*13*17 = 510510 <= 10! = 3628800, so a(7)=10. [edited by Jon E. Schoenfield, May 13 2018]

MATHEMATICA

Primorial[n_] := Product[ Prime[i], {i, n}]; a[n_] := Block[{k = 1}, While[(k!) < Primorial[n], k++ ]; k]; Table[ a[n], {n, 71}] (* Robert G. Wilson v, Apr 09 2004 *)

Module[{nn=100, pn, k=2}, pn=FoldList[Times, Prime[Range[nn]]]; Table[ While[ k!< pn[[n]], k++]; k, {n, nn}]] (* Harvey P. Dale, Dec 12 2018 *)

PROG

(PARI) a(n) = {my(pr = prod(k=1, n, prime(k)), k = 0); while (k! < pr, k++); k; } \\ Michel Marcus, May 14 2018

CROSSREFS

Cf. A000142, A002110, A073071, A093697.

Sequence in context: A287770 A039080 A093435 * A028749 A028764 A326070

Adjacent sequences:  A048961 A048962 A048963 * A048965 A048966 A048967

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 14 2007

STATUS

approved

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Last modified November 28 10:16 EST 2021. Contains 349401 sequences. (Running on oeis4.)