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A108585 a(n) = a(n-1) + 2*A005185(n+1), with a(1) = 2. 2

%I #12 Dec 20 2022 08:02:38

%S 2,6,12,18,26,36,46,58,70,82,98,114,130,150,168,188,210,232,256,280,

%T 304,328,360,388,416,448,480,512,544,584,618,652,692,734,772,812,856,

%U 898,942,988,1034,1082,1130,1178,1226,1274,1338,1386,1436,1496,1552,1604

%N a(n) = a(n-1) + 2*A005185(n+1), with a(1) = 2.

%H G. C. Greubel, <a href="/A108585/b108585.txt">Table of n, a(n) for n = 1..1000</a>

%t Hofstadter[n_]:= Hofstadter[n]= If[n<3, 1, Hofstadter[n-Hofstadter[n- 1]] + Hofstadter[n-Hofstadter[n-2]]];

%t a[n_]:= a[n]= If[n==1, 2, a[n-1] +2*Hofstadter[n+1]];

%t Table[a[n], {n,60}]

%o (SageMath)

%o @CachedFunction

%o def H(n): return 1 if (n<3) else H(n-H(n-1)) + H(n-H(n-2))

%o def a(n): return 2 if (n==1) else a(n-1) + 2*H(n+1)

%o [a(n) for n in range(1,61)] # _G. C. Greubel_, Dec 19 2022

%Y Cf. A005185, A108583.

%K nonn,less

%O 1,1

%A _Roger L. Bagula_, Jul 05 2005

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)