%I #9 Apr 17 2024 04:42:58
%S 0,1,126,1001,3876,10630,23751,46376,82251,135751,211880,316251,
%T 455126,635376,864501,1150630,1502501,1929501,2441626,3049501,3764380,
%U 4598126,5563251,6672876,7940751,9381255,11009376,12840751,14891626,17178876,19720005,22533126
%N Number of 5-member subsets of [5*n] whose elements sum to a multiple of n.
%H Alois P. Heinz, <a href="/A318626/b318626.txt">Table of n, a(n) for n = 0..10000</a>
%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1,1,-4,6,-4,1).
%F G.f.: -x*(5*x^8+106*x^7+527*x^6+608*x^5+629*x^4+624*x^3+503*x^2+122*x+1) / ((x^4+x^3+x^2+x+1) *(x-1)^5).
%F a(n) = (-250*n +216/5 + 625*n^4 -1250*n^3 +875*n^2)/24 +4* b(n)/5 for n>=1, where b(n) = b(n-5) = 4, -1, -1, -1, -1, 4, -1, -1, -1,.. 5-periodic for n>=0. - _R. J. Mathar_, Apr 17 2024
%t LinearRecurrence[{4,-6,4,-1,1,-4,6,-4,1},{0,1,126,1001,3876,10630,23751,46376,82251,135751},40] (* _Harvey P. Dale_, Jul 13 2019 *)
%Y Row n=5 of A318557.
%K nonn,easy
%O 0,3
%A _Alois P. Heinz_, Aug 30 2018