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%I #7 Jan 19 2019 20:22:21
%S 2,6,30,210,2310,29464,476928,9671392,222388792,6438663000,
%T 200560490130,7379606916000,299261862900000,13004421443456272,
%U 614231422273479360,31727029501157817600,1915248189055217892480,116762424492324428512272
%N a(n) = A000010(A006862(n)).
%p A006862 := proc(n) if n = 0 then 2; else 1+mul(ithprime(j),j=1..n) ; end if: end proc: A171989 := proc(n) numtheory[phi](A006862(n)) ; end proc: seq(A171989(n),n=1..18) ; # _R. J. Mathar_, Jan 30 2010
%o (PARI) a(n)=eulerphi(prod(i=1,n,prime(i))+1) \\ _Charles R Greathouse IV_, Mar 05 2013
%Y Cf. A000010, A006862.
%K nonn
%O 1,1
%A _Giovanni Teofilatto_, Jan 21 2010
%E a(1) inserted and extended beyond a(5) by _R. J. Mathar_, Jan 30 2010
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