A129284 - OEIS

%I #25 Feb 26 2024 01:59:14

%S 2,3,4,8,20,44,92,188,380,856,2148,5024,17616,58768,176320,755904,

%T 3305920,13885184,69634816,348174336,2385273856,14652403712,

%U 102566830080,849285738496,6035962949632,44017806979072,308166534991872,2380768960708608,23410894780694528

%N a(n) = A129150(n) / 4, where A129150(n) = n-th arithmetic derivative of 2^3.

%C In general, the trajectory of p^(p+1) under A003415 has a common factor p^p, and divided by p^p it gives the trajectory of p under A129283: n -> n + n'. Here we have the case p = 2, see A129151 and A129152 for p = 3 and 5. - _M. F. Hasler_, Nov 28 2019

%H Paolo P. Lava, <a href="/A129284/b129284.txt">Table of n, a(n) for n = 0..75</a>

%F a(n+1) = A129283(a(n)), a(0) = 2.

%o (Haskell) a129284 n = a129150 n `div` 4  -- _Reinhard Zumkeller_, Nov 01 2013, corrected by _M. F. Hasler_, Nov 29 2019

%o (PARI) A129284_upto(n)=A129150_upto(n)\4 \\ _M. F. Hasler_, Nov 29 2019

%Y Cf. A129285, A129286, A051674.

%K nonn

%O 0,1

%A _Reinhard Zumkeller_, Apr 07 2007

%E a(18)-a(28) from _Paolo P. Lava_, Apr 16 2012

%E Edited by _M. F. Hasler_, Nov 27 2019