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A239634 Initial digits of semiprimes in decimal representation. 3

%I

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

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

%U 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2

%N Initial digits of semiprimes in decimal representation.

%C a(n) = A000030(A001358(n)).

%H Reinhard Zumkeller, <a href="/A239634/b239634.txt">Table of n, a(n) for n = 1..10000</a>

%t First[IntegerDigits[#]]&/@Select[Range[300],PrimeOmega[#]==2&] (* _Harvey P. Dale_, Jul 24 2017 *)

%o (Haskell)

%o a239634 = a000030 . a001358

%Y Cf. A239639 (run lengths), A106146 (last digits).

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Mar 23 2014

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Last modified September 21 23:55 EDT 2019. Contains 327286 sequences. (Running on oeis4.)