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A222637 Squarefree part of the total number of arrangements of a set with n elements. 4
1, 2, 5, 1, 65, 326, 1957, 137, 109601, 986410, 9864101, 27126278, 7704505, 16926797486, 236975164805, 888656868019, 56874039553217, 966858672404690, 17403456103284421, 826664164906010, 6613313319248080001, 138879579704209680022, 3055350753492612960485 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

F. Luca and I. E. Shparlinski, On the squarefree parts of [ e n! ], Glasgow Math. J., 49 (2007), 391-403.

LINKS

Table of n, a(n) for n=0..22.

FORMULA

a(n) = core(A000522(n)).

MAPLE

A000522 := proc(n)

    add( n!/k!, k=0..n) ;

end proc:

A222637 := proc(n)

    A007913(A000522(n)) ;

end proc: # R. J. Mathar, Jan 16 2014

PROG

(PARI) a(n) = core(n! * polcoeff(exp(x + x*O(x^n)) / (1 - x), n))

CROSSREFS

Cf. A000522, A007913, A222638, A222639.

Sequence in context: A242783 A177250 A102786 * A190950 A159985 A259667

Adjacent sequences:  A222634 A222635 A222636 * A222638 A222639 A222640

KEYWORD

nonn

AUTHOR

Michel Marcus, Feb 27 2013

STATUS

approved

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Last modified February 18 02:20 EST 2018. Contains 299297 sequences. (Running on oeis4.)