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 A114854 Floor[n^(n/2)/n!! ]. 0
 1, 1, 1, 2, 3, 4, 8, 10, 20, 26, 51, 64, 128, 163, 326, 416, 834, 1067, 2148, 2755, 5559, 7147, 14449, 18613, 37696, 48638 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS This sequence is a second approximation of a double factorial analogue to Stirling's approximation to factorial. Note that a(n) is exact for n = 1, 2, 4. LINKS FORMULA a(n) = Floor[n^(n/2)/n!! ]. a(n) = Floor[Sqrt(A000312(n))/A006882(n)]. EXAMPLE a(10) = Floor[(10^5)/3840] = Floor[26.0416667] = 26. a(11) = Floor[(11^5.5)/10395] = Floor[51.3848715] = 51. CROSSREFS Cf. A000312, A006882, A055775. Sequence in context: A037171 A186417 A207644 * A127279 A050727 A102951 Adjacent sequences:  A114851 A114852 A114853 * A114855 A114856 A114857 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Feb 20 2006 STATUS approved

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