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 A077648 Initial digits of prime numbers. 12

%I

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

%T 1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,

%U 3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5

%N Initial digits of prime numbers.

%H Vincenzo Librandi, <a href="/A077648/b077648.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A000030(A000040(n)).

%t Table[First[IntegerDigits[Prime[n]]], {n, 1, 120}]

%o (MAGMA) [Intseq(p)[#Intseq(p)]: p in PrimesUpTo(600)]; // _Bruno Berselli_, Feb 14 2013

%o (PARI) a(n) = digits(prime(n))[1]; \\ _Michel Marcus_, Feb 11 2017

%Y Cf. A000030, A000040.

%K base,nonn

%O 1,1

%A _Labos Elemer_, Nov 19 2002

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Last modified September 17 04:49 EDT 2019. Contains 327119 sequences. (Running on oeis4.)