A155590 - OEIS

%I #26 Jul 30 2024 07:03:31

%S 1,8,52,350,2416,16838,117712,823670,5765056,40354118,282476272,

%T 1977328790,13841291296,96889018598,678223089232,4747561542710,

%U 33232930635136,232630514118278,1628413598172592,11398895185897430,79792266298660576,558545864085381158,3909821048587182352

%N a(n) = 7^n + 2^n - 1.

%H Paolo Xausa, <a href="/A155590/b155590.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (10,-23,14).

%F G.f.: 1/(1-7*x)+1/(1-2*x)-1/(1-x).

%F E.g.f.: exp(7*x)+exp(2*x)-exp(x).

%F a(n) = 9*a(n-1)-14*a(n-2)-6 with a(0) = 1, a(1) = 8. - _Vincenzo Librandi_, Jul 21 2010

%F a(n) = A074602(n)-1. - _R. J. Mathar_, Mar 10 2022

%t Table[7^n + 2^n - 1, {n, 0, 25}] (* _Paolo Xausa_, Jul 30 2024 *)

%o (PARI) a(n)=7^n+2^n-1 \\ _Charles R Greathouse IV_, Sep 24 2015

%Y Cf. A074501, A074600, A005057, A005056, A099393, A155588, A155590.

%K nonn,easy

%O 0,2

%A _Mohammad K. Azarian_, Jan 24 2009