Search: id:A067847
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%I A067847
%S A067847 1,2,3,5,9,15,27,40,63,100,180,248,459,696,1019,1299,2495,3219,6011,
%T A067847 7986,11247,17029,32567,39501,53017,79775,97251,126981,245675,301054,
%U A067847 582853,668274,921616,1382954,1811949,2097059,4088346,6142187,8417004
%N A067847 Number of divisors d of n! such that d+1 is prime.
%H A067847 Ray Chandler, <a href="b067847.txt">Table of n, a(n) for n=1..42</a>
%F A067847 a(n) = A067513(A000142(n)).
%e A067847 a(5)=9 because the divisors of 5!=120 are 1, 2, 3, 4, 5, 6, 8, 10, 12, 
               15, 20, 24, 30, 60 and 120 and the primes are 2, 3, 5, 7, 11, 13, 
               31, 41 and 61
%o A067847 (PARI) a(n)=s=0;fordiv (n!,i,if(isprime(n!/i+1),s=s+1));return(s);
%Y A067847 Cf. A067513, A156190.
%Y A067847 Sequence in context: A005169 A129852 A065954 this_sequence A022858 A090905 
               A065956
%Y A067847 Adjacent sequences: A067844 A067845 A067846 this_sequence A067848 A067849 
               A067850
%K A067847 nonn
%O A067847 1,2
%A A067847 Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 14 2002
%E A067847 More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 19 
               2002
%E A067847 More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Mar 13 2002
%E A067847 More terms from Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 26 2004
%E A067847 a(28)=118584 from Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 07 2004
%E A067847 Corrected a(28)=126981 and added a(29)-a(31) by Ray Chandler (rayjchandler(AT)sbcglobal.net), 
               Feb 03 2009
%E A067847 a(32)-a(42) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 05 
               2009

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