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A248592 Denominators of the (simplified) rational numbers n*2^(n - 1)/(n - 1)! . 4
1, 1, 1, 3, 3, 5, 45, 315, 35, 567, 14175, 51975, 467775, 868725, 2837835, 638512875, 638512875, 1206079875, 97692469875, 371231385525, 441942125625, 17717861581875, 2143861251406875, 16436269594119375, 5917057053882975, 284473896821296875, 1780595872696265625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..27.

James Burling, Another Special Rational Sequence

FORMULA

a(n) = denom(n * 2^(n - 1) / (n - 1)!).

a(n) = denom(g(1, n)) where g(m, n) = m if m = n; 2g(m + 1, n)/m otherwise.

MAPLE

A248592 := proc(n)

    n*2^(n-1)/(n-1)! ;

    denom(%) ;

end proc:

seq(A248592(n), n=1..30) ; # R. J. Mathar, Oct 10 2014

PROG

(PARI) vector(40, n, denominator(n*2^(n - 1)/(n - 1)!)) \\ Michel Marcus, Oct 09 2014

CROSSREFS

Cf. A248591 (numerators).

Has same start as A241591 but is a different sequence.

Sequence in context: A170919 A280779 A241591 * A132809 A265960 A279062

Adjacent sequences:  A248589 A248590 A248591 * A248593 A248594 A248595

KEYWORD

frac,nonn

AUTHOR

James Burling, Oct 09 2014

EXTENSIONS

More terms from Michel Marcus, Oct 09 2014

STATUS

approved

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Last modified August 14 10:58 EDT 2022. Contains 356116 sequences. (Running on oeis4.)