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Initial digit of n-th superfactorial.
1

%I #20 Mar 21 2020 16:02:43

%S 1,1,2,1,2,3,2,1,5,1,6,2,1,7,6,9,1,6,4,5,1,6,7,1,1,1,7,7,2,2,5,4,1,1,

%T 3,3,1,1,8,1,1,4,6,4,1,1,7,1,2,1,4,6,5,2,5,6,4,1,4,6,5,2,8,1,2,1,9,3,

%U 8,1,1,1,9,4,1,3,6,9,1,9,6,3,1,7,2,6,1,3,6,1,1,2,2,3,3,3,3,3,3,2,2

%N Initial digit of n-th superfactorial.

%H Chai Wah Wu, <a href="/A332842/b332842.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = A000030(A000178(n)).

%e a(6) = 2 because A000178(6) = 24883200.

%o (PARI) a(n) = digits(prod(k=2, n, k!))[1]; \\ _Michel Marcus_, Feb 26 2020

%o (Python)

%o def A332842(n):

%o m, k = 1, 1

%o for i in range(2,n+1):

%o k *= i

%o m *= k

%o return int(str(m)[0]) # _Chai Wah Wu_, Mar 17 2020

%Y Cf. A000030, A000178, A008905.

%K easy,nonn,base

%O 0,3

%A _Eder Vanzei_, Feb 26 2020