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%I #19 Jun 17 2016 09:25:55
%S 0,0,1,2,4,7,10,15,20,27,34,44,53,66,78,94,109,129,147,171,193,221,
%T 247,280,310,348,383,426,466,515,560,615,666,727,784,852,915,990,1060,
%U 1142,1219,1309,1393,1491,1583,1689,1789,1904,2012,2136,2253,2386,2512
%N Number of non-Abelian metacyclic groups of order p^n (p odd).
%H Colin Barker, <a href="/A007983/b007983.txt">Table of n, a(n) for n = 1..1000</a>
%H Steven Liedahl, <a href="http://dx.doi.org/10.1006/jabr.1996.0381">Enumeration of metacyclic p-groups</a>, J. Algebra 186 (1996), no. 2, 436-446.
%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-1,-2,-1,2,1,-1).
%F a(n) = A136185(n) - floor(n/2) - 1. - _Eric M. Schmidt_, Jan 08 2015
%F G.f.: -x^3*(x^4-x-1) / ((x-1)^4*(x+1)^2*(x^2+x+1)). - _Colin Barker_, Jan 12 2015
%t LinearRecurrence[{1,2,-1,-2,-1,2,1,-1},{0,0,1,2,4,7,10,15},60] (* _Harvey P. Dale_, Jun 17 2016 *)
%o (PARI) concat([0,0], Vec(-x^3*(x^4-x-1)/((x-1)^4*(x+1)^2*(x^2+x+1)) + O(x^100))) \\ _Colin Barker_, Jan 12 2015
%K nonn,easy
%O 1,4
%A S. Liedahl
%E Initial terms added and sequence extended (using A136185) by _Eric M. Schmidt_, Jan 08 2015
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