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A126019 a(0)=1, a(1)=2; for n>1, a(n)=3*a(n-1)+4*a(n-2)+5. 0

%I #13 May 30 2020 10:54:07

%S 1,2,15,58,239,954,3823,15290,61167,244666,978671,3914682,15658735,

%T 62634938,250539759,1002159034,4008636143,16034544570,64138178287,

%U 256552713146,1026210852591,4104843410362,16419373641455,65677494565818

%N a(0)=1, a(1)=2; for n>1, a(n)=3*a(n-1)+4*a(n-2)+5.

%C First prime terms are a(n) with a = 1, 4, 6, 18, 88.

%F a(n) = (28*4^n + 27(-1)^n - 25)/30.

%F G.f. = (1 - 2*x + 6*x^2)/(1 - 4*x - x^2 + 4*x^3).

%t RecurrenceTable[{a[0]==1,a[1]==2,a[n]==3a[n-1]+4a[n-2]+5},a,{n,30}] (* _Harvey P. Dale_, May 30 2020 *)

%o (Sage)

%o from sage.combinat.sloane_functions import recur_gen2b

%o it = recur_gen2b(1,2,3,4, lambda n: 5)

%o [next(it) for i in range(24)] # _Zerinvary Lajos_, Jul 16 2008

%K nonn

%O 0,2

%A _Zak Seidov_, Feb 26 2007

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)