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%I #35 Sep 06 2023 11:49:02
%S 4,4,2,2,3,2,2,3,2,1,4,1,1,3,1,2,2,2,1,4,0,1,3,2,1,2,2,2,2,1,1,3,0,2,
%T 2,2,1,2,2,1,2,1,1,3,2,1,3,1,1,2,2,0,2,0,2,1,2,2,1,2,2,3,0,1,3,2,1,2,
%U 1,1,2,1,1,2,1,2,2,1,1,1,1,1,4,1,0,3,1,1,3,0,1,2,1,1,2,1,1,2,1,2,1,2,1,3,1,1
%N Number of primes between 10n and 10n+9.
%C If n runs through the primes, the subsequence 2, 2, 2, 3, 1, 3, 2, 4, 2, 1, 3, 2, 1, 3, 1, 0, 2, 3, 2,... is created. - _R. J. Mathar_, Jul 19 2012
%C Since 431, 433, and 439 are all prime, a(43)=3. - _Bobby Jacobs_, Sep 25 2016
%H Michael De Vlieger, <a href="/A038800/b038800.txt">Table of n, a(n) for n = 0..10000</a>
%H A. Frank and P. Jacqueroux, <a href="http://www.paulcooijmans.com/others/intcontest.pdf">International Contest</a>, 2001. Numerators of Item 23
%t Table[Count[Range[10 n, 10 n + 9], p_ /; PrimeQ@ p], {n, 0, 105}] (* _Michael De Vlieger_, Sep 25 2016 *)
%o (PARI) a(n) = primepi(10*n+9) - primepi(10*n); \\ _Michel Marcus_, Sep 26 2016
%Y Cf. A055781, A055782, A055783, A055784.
%Y Positions of 4's: {0} U A007811.
%Y Cf. A098592.
%K easy,nonn
%O 0,1
%A _Jeff Burch_
%E a(43) corrected by _Bobby Jacobs_, Sep 25 2016
%E a(101) and a(104) corrected by _Michael De Vlieger_, Sep 25 2016
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