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A050221 a(n) = number of sets of consecutive primes whose arithmetic mean is A060863(n). 4

%I #9 Jul 07 2015 09:39:17

%S 1,1,1,2,1,1,2,1,3,1,3,2,2,1,1,2,2,2,2,5,2,3,2,4,2,1,3,2,1,1,2,2,1,5,

%T 1,4,2,2,1,3,1,2,1,1,4,1,2,1,1,1,1,3,2,2,2,1,1,5,3,1,1,1,2,2,2,1,1,3,

%U 3,1,4,1,2,2,1,3,3,1,3,1,2,1,1,3,1,1,1,2,1,3,1,1,1,2,3,1,1,2,4,4,2,4,1,3,2

%N a(n) = number of sets of consecutive primes whose arithmetic mean is A060863(n).

%C Essentially A122821 with the 0's removed.

%F a(n) = A122821(A060863(n)).

%e For n=4; A060863(4) = 5. the two sets are 5/1 = 5, (3+5+7)/3 = 5. so a(4)=2.

%t f[n_]:=Block[{i=1,j,c=0,m},While[Prime[i]<=n, j=1; While[m=Sum[Prime[k],{k,i,i+j-1}]/j; If[m==n,c++ ]; m<n, j++ ]; i++ ]; c]; Select[Table[f[n],{n,160}],#>0&] (* _Ray Chandler_, Oct 03 2006 *)

%Y Cf. A060863, A122821.

%K easy,nonn

%O 1,4

%A _Naohiro Nomoto_, May 08 2003

%E Extended by _Ray Chandler_, Oct 03 2006

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Last modified April 25 09:49 EDT 2024. Contains 371967 sequences. (Running on oeis4.)