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A083533 First difference sequence of A002202. Difference between consecutive possible values of phi(n), the Euler totient function A000010.

%I A083533 #29 May 14 2025 14:03:06
%S A083533 1,2,2,2,2,2,4,2,2,2,2,4,2,2,4,4,2,2,2,2,4,2,2,2,2,4,2,4,2,6,2,2,2,4,
%T A083533 4,4,4,2,2,2,2,2,2,4,4,6,2,2,2,4,2,2,4,4,2,6,4,2,2,2,2,4,4,2,2,4,6,2,
%U A083533 4,2,2,4,4,2,2,4,4,2,2,2,2,4,6,2,10,2,4,4,2,2,4,2,2,4,4,2,6,4,2,2,4,6,4,2,4
%N A083533 First difference sequence of A002202. Difference between consecutive possible values of phi(n), the Euler totient function A000010.
%H A083533 Reinhard Zumkeller, <a href="/A083533/b083533.txt">Table of n, a(n) for n = 1..10000</a>
%F A083533 a(n) = A002202(n+1) - A002202(n).
%t A083533 t=Table[EulerPhi[w], {w, 1, 25000}]; u=Union[%]; Delete[u-RotateRight[u], 1]
%o A083533 (Haskell)
%o A083533 a083533 n = a083533_list !! (n-1)
%o A083533 a083533_list = zipWith (-) (tail a002202_list) a002202_list
%o A083533 -- _Reinhard Zumkeller_, Nov 26 2015
%o A083533 (PARI) lista(lim) = {my(k1 = 1, k2 = 1); while(k1 < lim, until(istotient(k2), k2++); print1(k2 - k1, ", "); k1 = k2);} \\ _Amiram Eldar_, Nov 16 2024
%Y A083533 Cf. A000010, A002202, A005277, A083531, A083532, A083534, A083535, A083536.
%K A083533 nonn
%O A083533 1,2
%A A083533 _Labos Elemer_, May 20 2003