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Fourth quadrisection of Jacobsthal numbers A001045: a(n)=16a(n-1)-5.
5

%I #26 Mar 17 2024 02:10:41

%S 3,43,683,10923,174763,2796203,44739243,715827883,11453246123,

%T 183251937963,2932031007403,46912496118443,750599937895083,

%U 12009599006321323,192153584101141163,3074457345618258603,49191317529892137643

%N Fourth quadrisection of Jacobsthal numbers A001045: a(n)=16a(n-1)-5.

%C Jacobsthal numbers ending with the decimal digit 3. - _Jianing Song_, Aug 30 2022

%H Vincenzo Librandi, <a href="/A141060/b141060.txt">Table of n, a(n) for n = 0..200</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (17,-16).

%F a(n) = A139792(n) + A013776(n).

%F a(n+1) - a(n) = 10*A013709(n) = 40*A001025(n).

%F G.f.: (3-8*x)/((1-x)*(1-16*x)). [_Colin Barker_, Apr 05 2012]

%F a(0)=3, a(1)=43, a(n)=17*a(n-1)-16*a(n-2). - _Harvey P. Dale_, Mar 16 2015

%F From _Jianing Song_, Aug 30 2022: (Start)

%F a(n) = A001045(4*n+3).

%F a(n) = 10*A141032(n) + 3 = 20*A098704(n+1) + 1 = 40*A131865(n-1) + 1 for n >= 1. (End)

%t LinearRecurrence[{17,-16},{3,43},30] (* _Harvey P. Dale_, Mar 16 2015 *)

%o (Magma) [(1/3)*(1+8*16^n): n in [0..25]]; // _Vincenzo Librandi_, May 25 2011

%o (PARI) a(n)=8*16^n\3+1 \\ _Charles R Greathouse IV_, May 25, 2011

%Y The other quadrisections of A001045 are A195156 (first), A139792 (second), and A144864 (third).

%K nonn,easy,less

%O 0,1

%A _Paul Curtz_, Jul 30 2008

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Last modified September 22 17:55 EDT 2024. Contains 376119 sequences. (Running on oeis4.)