A171471 - OEIS

%I #7 Mar 22 2018 16:37:13

%S 35,225,837,3213,12573,49725,197757,788733,3150333,12592125,50350077,

%T 201363453,805380093,3221372925,12885196797,51540197373,206159609853,

%U 824636080125,3298539601917,13194148970493,52776577007613

%N a(n) = 6*a(n-1)-8*a(n-2)-9 for n > 2; a(0) = 35, a(1) = 225, a(2) = 837.

%C Related to Reverse and Add trajectory of 22 in base 2: A061561(4*n+1) = a(n).

%H Vincenzo Librandi, <a href="/A171471/b171471.txt">Table of n, a(n) for n = 0..500</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).

%F a(n) = 48*4^n+18*2^n-3 for n > 0.

%F G.f.: (35-20*x-248*x^2+224*x^3)/((1-x)*(1-2*x)*(1-4*x)).

%t LinearRecurrence[{7,-14,8},{35,225,837,3213},30] (* _Harvey P. Dale_, Mar 22 2018 *)

%o (PARI) {m=22; v=concat([35, 225, 837], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]-9); v}

%Y Cf. A061561, A171470, A171472, A171473.

%K nonn,easy

%O 0,1

%A _Klaus Brockhaus_, Dec 09 2009