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 A253207 a(n) = number of permutations of (1,2,...,n) producible by an ordered quadruple of distinct transpositions. 1

%I

%S 11,59,359,1799,7091,22995,64143,159093,359348,752180,1478204,2754752,

%T 4906202,8402522,13907394,22337388,34933761,53348561,79746821,

%U 116926733,168459797,238853045,333735545,460071495,626402322,843120306,1122776354

%N a(n) = number of permutations of (1,2,...,n) producible by an ordered quadruple of distinct transpositions.

%H Colin Barker, <a href="/A253207/b253207.txt">Table of n, a(n) for n = 4..1000</a>

%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (9,-36,84,-126,126,-84,36,-9,1).

%F a(n) = n!*(1/(384*(n-8)!)+1/(24*(n-7)!)+13/(72*(n-6)!)+1/(5*(n-5)!)+1/(8*(n-4)!)+1/(3*(n-3)!)) for n>=8.

%o (PARI) Vec(-x^4*(2*x^8-18*x^7+72*x^6-168*x^5+254*x^4-232*x^3+224*x^2-40*x+11)/(x-1)^9 + O(x^100)) \\ _Colin Barker_, Dec 30 2014

%Y Cf. A000914, for two transpositions, and A253171, for three.

%K nonn,easy

%O 4,1

%A _Andrew Woods_, Dec 28 2014

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Last modified August 10 02:02 EDT 2020. Contains 336365 sequences. (Running on oeis4.)