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A095997 Number of divisors of n! that are coprime to n. 1
1, 1, 2, 2, 8, 2, 30, 12, 32, 10, 270, 12, 792, 72, 144, 336, 5376, 96, 14688, 432, 1520, 1600, 96000, 960, 48576, 7392, 48384, 7056, 917280, 720, 2332800, 172800, 122880, 122880, 304128, 31104, 19595520, 559872, 1119744, 262656, 102435840, 46080, 258048000, 3225600, 3386880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(p_i) < a(p_j) for i<j.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..1000

MATHEMATICA

f[n_] := Length[ Select[ Divisors[n! ], GCD[ #, n] == 1 &]]; Table[ f[n], {n, 33}]

PROG

(PARI) a(n)={if(n<=2, 1, numdiv(Mat(select(f->n%f[1], Col(factor(n!))))))} \\ Andrew Howroyd, Nov 05 2019

CROSSREFS

Cf. A000142, A027423.

Sequence in context: A222821 A245497 A086328 * A274139 A283995 A056189

Adjacent sequences:  A095994 A095995 A095996 * A095998 A095999 A096000

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jul 19 2004, based on a suggestion from Leroy Quet, Jun 18 2004

EXTENSIONS

Terms a(34) and beyond from Andrew Howroyd, Nov 05 2019

STATUS

approved

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Last modified January 27 19:07 EST 2021. Contains 340479 sequences. (Running on oeis4.)