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

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, 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, 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

Offset

1,4

Comments

Essentially A122821 with the 0's removed.

Links

Table of n, a(n) for n=1..105.

Formula

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

Example

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

Mathematica

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 *)

Crossrefs

Cf. A060863, A122821.

Sequence in context: A247299 A127586 A055893 * A213235 A113279 A213234

Adjacent sequences: A050218 A050219 A050220 * A050222 A050223 A050224

Keyword

easy,nonn

Author

Naohiro Nomoto, May 08 2003

Extensions

Extended by Ray Chandler, Oct 03 2006

Status

approved