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a(n) = (n^7 - n)/42.
2

%I #17 Sep 08 2022 08:44:50

%S 0,0,3,52,390,1860,6665,19608,49932,113880,238095,463980,853138,

%T 1494012,2509845,4068080,6391320,9769968,14576667,21282660,30476190,

%U 42883060,59389473,81067272,109201700,145321800,191233575,249056028,321260202,410711340,520714285

%N a(n) = (n^7 - n)/42.

%H G. C. Greubel, <a href="/A030180/b030180.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (8,-28,56,-70,56,-28,8,-1).

%F a(n) = A133499(n)/42. - _Michel Marcus_, Aug 30 2013

%F From _Stefano Spezia_, Dec 29 2019: (Start)

%F O.g.f.: x^2*(3 + 28*x + 58*x^2 + 28*x^3 + 3*x^4)/(1 - x)^8.

%F E.g.f.: (1/42)*exp(x)*x^2*(63 + 301*x + 350*x^2 + 140*x^3 + 21*x^4 + x^5).

%F (End)

%p seq( (n^7-n)/42, n=0..35); # _G. C. Greubel_, Dec 28 2019

%t Table[(n^7-n)/42, {n,0,35}] (* _G. C. Greubel_, Dec 28 2019 *)

%t LinearRecurrence[{8,-28,56,-70,56,-28,8,-1},{0,0,3,52,390,1860,6665,19608},40] (* _Harvey P. Dale_, May 14 2022 *)

%o (PARI) a(n) = (n^7-n)/42; \\ _Michel Marcus_, Aug 30 2013

%o (Magma) [(n^7-n)/42: n in [0..35]]; // _G. C. Greubel_, Dec 28 2019

%o (Sage) [(n^7-n)/42 for n in (0..35)] # _G. C. Greubel_, Dec 28 2019

%o (GAP) List([0..35], n-> (n^7-n)/42); # _G. C. Greubel_, Dec 28 2019

%Y Cf. A133499 (n^7-n).

%K nonn

%O 0,3

%A Charlton Harrison (charlton(AT)bach.dynet.com)