A248592 Denominators of the (simplified) rational numbers n*2^(n - 1)/(n - 1)! .
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
Offset: 1
Links
- James Burling, Another Special Rational Sequence
Programs
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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
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PARI
vector(40, n, denominator(n*2^(n - 1)/(n - 1)!)) \\ Michel Marcus, Oct 09 2014
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.
Extensions
More terms from Michel Marcus, Oct 09 2014