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A095240 Variant of A095236, where first two people choose payphones at the ends. 8
1, 2, 2, 4, 4, 16, 32, 48, 96, 384, 3072, 9216, 36864, 46080, 184320, 483840, 3870720, 7741440, 82575360, 743178240, 23781703680, 59454259200, 475634073600, 2497078886400, 39953262182400, 22473709977600, 85614133248000 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
A non-monotonic sequence: a(25) > a(26).
a(n) > a(n+1) for n = 25, 33, 49, 57, 65, 81, 97, 98, 113, 129, 130, 131, 145, 161, 162, 177, 193, 194, 195, 197, ... - Max Alekseyev, Mar 14 2019
LINKS
Simon Wundling, About a combinatorial problem with n seats and n people, arXiv:2303.18175 [math.CO], 2023. (German)
FORMULA
For n>1, a(n) = A095239(n-1)/(n-1) * 2. - Max Alekseyev, Mar 14 2019
For n>1, a(n) = 2 * Product_{j=1..n-1} 2^(d(n,j)) * (d(n,j))! * (b(n,j) - d(n,j))! (See A095236 for definition and calculation of b(n,j) and d(n,j)). - Simon Wundling, May 21 2023
EXAMPLE
For example, in a 6-pay-phone situation, person A must pick either pay-phone 1 or pay-phone 6.
CROSSREFS
Sequence in context: A066781 A112869 A086117 * A110428 A076928 A286737
KEYWORD
nonn
AUTHOR
Matthew Vandermast, Jul 03 2004
EXTENSIONS
Edited by Max Alekseyev, Mar 14 2019
STATUS
approved

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Last modified December 10 09:31 EST 2023. Contains 367710 sequences. (Running on oeis4.)