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%I #19 Sep 08 2022 08:45:54
%S 6,76,386,1251,3126,6606,12426,21461,34726,53376,78706,112151,155286,
%T 209826,277626,360681,461126,581236,723426,890251,1084406,1308726,
%U 1566186,1859901,2193126,2569256,2991826,3464511,3991126,4575626
%N a(n) = (35*n^4 - 35*n^3 + 55*n^2 - 25*n + 6)/6.
%C Second bisection of A175898.
%H Vincenzo Librandi, <a href="/A181343/b181343.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + 140 for n > 4; a(1)=6, a(2)=76, a(3)=386, a(4)=1251.
%F G.f.: x*(6 + 46*x + 66*x^2 + 21*x^3 + x^4)/(1-x)^5.
%F a(-n+1) = A181342(n). - _Bruno Berselli_, Aug 23 2011
%t LinearRecurrence[{5,-10,10,-5,1},{6,76,386,1251,3126},30] (* _Harvey P. Dale_, Dec 06 2016 *)
%o (Magma) [ (35*n^4-35*n^3+55*n^2-25*n+6)/6: n in [1..30] ];
%o (PARI) a(n)=(35*n^4-35*n^3+55*n^2-25*n+6)/6 \\ _Charles R Greathouse IV_, Jul 06 2017
%Y Cf. A175898, A181342.
%K nonn,easy
%O 1,1
%A _Klaus Brockhaus_, Oct 14 2010
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